Battery

ABSTRACT

A battery includes: a cylindrical battery case; and an electrode body disposed in the battery case, and including a positive plate, a negative plate, and a separator disposed between the positive plate and the negative plate. A spacer formed of a dense body and an electrolyte storage space storing an electrolyte are provided between the electrode body and the battery case on one end or both ends of the battery case in an axial direction of the electrode body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese patent application Nos.2012-170503 filed on Jul. 31, 2012, and 2013-133126, 2013-133159,2013-133160, 2013-133161, 2013-133166, and 2013-133167 respectivelyfiled on Jun. 25, 2013, which are incorporated by reference.

FIELD

The present invention relates to a technique of the internal structureof a battery.

BACKGROUND

In these years, the need of a battery at low cost is increasing.Therefore, for example, such a battery is developed in which the batteryincludes an electrode group formed of a positive plate, a negativeplate, and a separator impregnated with an electrolyte in a batterycase, and the length of an electrode group is shortened in the axialdirection of the battery case and a filler is included in the remainingspace in the battery case. Thus, the amount of electrodes used isdecreased, battery costs are decreased, and the unsteadiness of theelectrode group in the battery case is suppressed because of the filleras compared with the case where an electrode group is formed across theoverall length of a battery in the axial direction (see DE 200 16 213U1).

In the existing technique, the length of the electrode group isshortened in the axial direction of the battery case, and the filler isincluded in the remaining space in the battery case. However, it isdemanded that the amount of electrodes used is decreased using aconfiguration different from the configuration of the existingtechnique.

SUMMARY

The following presents a simplified summary of the invention disclosedherein in order to provide a basic understanding of some aspects of theinvention. This summary is not an extensive overview of the invention.It is intended to neither identify key or critical elements of theinvention nor delineate the scope of the invention. Its sole purpose isto present some concepts of the invention in a simplified form as aprelude to the more detailed description that is presented later.

Disclosed herein is a technique that can decrease the amount ofelectrodes used with respect to an accommodation space in a case such asa battery case while suppressing the unsteadiness of an electrode groupin the case.

A battery according to one aspect of the present invention includes: acase having an accommodation space in a tubular interior; and anelectrode body disposed in the accommodation space in the case, andincluding a positive plate, a negative plate, and a separator disposedbetween the positive plate and the negative plate. A spacer formed of adense body and an electrolyte storage space in which an electrolyte isstored are provided between the electrode body and the case on one endor both ends of the case in an axial direction of the electrode body.

A battery according to another aspect of the present invention includes:a case having an accommodation space in the case; and an electrode bodydisposed in the accommodation space in the case, and including aplurality of electrode plates having an active material layer includingan active material and a substrate, and separator. At least one of theelectrode plates has an active material layer forming portion in whichthe active material layer is formed on the substrate and a non-activematerial layer forming portion in which the active material layer is notformed. At least the non-active material layer forming portion contactsan inner wall of the case.

A battery according to still another aspect of the present inventionincludes: a tubular case; and an electrode body having a positive plateand a negative plate wound with a separator interposed therebetween. Theelectrode body is accommodated in the case, and includes a spacer onboth ends of the electrode body in a winding axial direction. At least apart of an outer circumferential portion of the spacer contacts an innerwall surface of the case.

A battery according to yet another aspect of the present inventionincludes: a battery case including a tubular portion having anaccommodation space in the tubular portion; an electrode bodyaccommodated in the accommodation space, including a positive plate, anegative plate, and a separator disposed between the positive plate andthe negative plate, the positive plate, the negative plate, and theseparator being disposed as contacting an inner face of the tubularportion along the inner face of the tubular portion, the electrode bodyincluding a tubular hollow portion; and a spacer accommodated in thehollow portion and contacting an inner circumferential face of theelectrode body.

A battery according to yet another aspect of the present inventionincludes: a conductive battery case; a cylindrical electrode bodyaccommodated in the battery case and including a positive plate, anegative plate, and a separator disposed between the positive plate andthe negative plate, the cylindrical electrode body including a diameterreducing portion whose outer diameter is smaller than an inner diameterof the battery case; and a conductive spacer disposed between an outercircumferential face of the diameter reducing portion and an inner faceof the battery case to electrically connect the cylindrical electrodebody to the battery case.

A battery according to yet another aspect of the present inventionincludes: a battery case including a tubular portion; a cylindricalelectrode body including a positive plate, a negative plate, and aseparator disposed between the positive plate and the negative plate,the cylindrical electrode body including a diameter reducing portionwhose outer diameter is smaller than an inner diameter of the tubularportion; and a spacer disposed between the tubular portion and thecylindrical electrode body, the spacer contacting an inner face of thetubular portion and an outer face of the cylindrical electrode body. Thecylindrical electrode body in the tubular portion is disposed at aposition at which an axis of the cylindrical electrode body is differentfrom an axis of the tubular portion.

A battery according to yet another aspect of the present inventionincludes: a case having an accommodation space in the case; and anelectrode body disposed in the accommodation space in the case andincluding a plurality of electrode plates having an active materiallayer including an active material and a substrate, and separator. Atleast one of the plurality of electrode plates or the separator includesa wide width portion and a narrow width portion whose widths aredifferent from each other in a direction vertical to a longitudinaldirection of the electrode body or the separator.

The battery is capable of decreasing the amount of electrodes used withrespect to an accommodation space in a case such as a battery case whilesuppressing the unsteadiness of an electrode body in the case.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other features of the invention will become apparentfrom the following description and drawings of an illustrativeembodiment of the invention in which:

FIG. 1 shows a cross sectional view of a battery according to a firstembodiment in a first aspect of the present invention;

FIG. 2 shows a perspective view of an exemplary spacer according to thefirst embodiment in the first aspect of the present invention;

FIG. 3 shows a perspective view of an exemplary spacer according to thefirst embodiment in the first aspect of the present invention;

FIG. 4 shows a plan view of an exemplary spacer according to the firstembodiment in the first aspect of the present invention;

FIG. 5 shows a perspective view of an exemplary spacer according to thefirst embodiment in the first aspect of the present invention;

FIG. 6 shows a cross sectional view of a battery according to a secondembodiment in the first aspect of the present invention;

FIG. 7 shows a perspective view of an exemplary spacer according to thesecond embodiment in the first aspect of the present invention;

FIGS. 8A to 8C show perspective views of another exemplary spaceraccording to the present invention;

FIGS. 9A to 9C show perspective views of still another exemplary spaceraccording to the present invention;

FIGS. 10A to 10C show perspective views of yet another exemplary spaceraccording to the present invention;

FIG. 11 shows a cross sectional view of Sample 2 in Example 1;

FIG. 12 shows a cross sectional view of Sample 3 in Example 1;

FIG. 13 shows a cross sectional view of Sample 4 in Example 1;

FIG. 14 shows a perspective view of a longitudinal section of a batteryaccording to an embodiment in a second aspect of the present invention;

FIG. 15 shows a vertical cross sectional view of the battery;

FIG. 16 shows an exploded perspective view of the battery;

FIG. 17 shows a plan view of a metal plate on which an active materialis coated;

FIG. 18 shows a perspective view of a metal plate on which an activematerial is coated;

FIG. 19 shows a plan view of a metal plate on which an active materialis coated in accordance with another embodiment in the second aspect ofthe present invention;

FIG. 20 shows a perspective view of a longitudinal section of a batteryaccording to a first embodiment in a third aspect of the presentinvention;

FIG. 21 shows a vertical cross sectional view of the battery;

FIG. 22 shows an exploded perspective view of the battery;

FIG. 23 shows a horizontal cross sectional view of an electrode body;

FIG. 24A shows a horizontal cross sectional view of a battery in thecase where no spacer is provided;

FIG. 24B shows a horizontal cross sectional view of a battery in thecase where a spacer is provided;

FIG. 25 shows a perspective view of a spacer;

FIG. 26 shows a perspective view of a longitudinal section of a batteryaccording to a first embodiment in a fourth aspect of the presentinvention;

FIG. 27 shows a vertical cross sectional view of the battery;

FIG. 28 shows a cross sectional view of the battery;

FIG. 29 shows an exploded perspective view of the battery;

FIG. 30 shows a cross sectional view of a battery according to a secondembodiment in the fourth aspect of the present invention;

FIG. 31 shows a cross sectional view of a battery according to a thirdembodiment in the fourth aspect of the present invention;

FIG. 32 shows a cross sectional view of a battery according to a fourthembodiment in the fourth aspect of the present invention;

FIG. 33 shows a perspective view of a longitudinal section of a batteryaccording to a first embodiment in a fifth aspect of the presentinvention;

FIG. 34 shows a vertical cross sectional view of the battery;

FIG. 35 shows a cross sectional view of the battery;

FIG. 36 shows an exploded perspective view of the battery;

FIG. 37 shows a perspective view in a state in which a spacer in a meshform is mounted on an electrode body in accordance with a secondembodiment in the fifth aspect of the present invention;

FIG. 38 shows a perspective view in a state in which a spacer in a coilform is mounted on an electrode body in accordance with a thirdembodiment in the fifth aspect of the present invention;

FIG. 39 shows a perspective view in a state in which a spacer in a coilspring form is mounted on an electrode body in accordance with adifferent embodiment in the fifth aspect of the present invention;

FIG. 40 shows a perspective view in a state in which a spacer in a leafspring form is mounted on an electrode body in accordance with adifferent embodiment in the fifth aspect of the present invention;

FIG. 41 shows a perspective view of a longitudinal section of a batteryaccording to a first embodiment in a sixth aspect of the presentinvention;

FIG. 42 shows a vertical cross sectional view of the battery;

FIG. 43 shows a cross sectional view of the battery;

FIG. 44 shows an exploded perspective view of the battery;

FIG. 45 shows a cross sectional view of a battery according to a secondembodiment in the sixth aspect of the present invention;

FIG. 46 shows a perspective view of a longitudinal section of a batteryaccording to one embodiment in a seventh aspect of the presentinvention;

FIG. 47 shows a vertical cross sectional view of the battery;

FIG. 48 shows an exploded perspective view of the battery;

FIG. 49 shows a plan view of a metal plate on which an active materialis coated;

FIG. 50 shows a perspective view of a metal plate on which an activematerial is coated; and

FIG. 51 shows a plan view of a metal plate on which an active materialis coated in accordance with another embodiment in the seventh aspect ofthe present invention.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the present invention will be describedhereinafter.

Outline of Embodiments

According to an aspect of the present invention, there is provided abattery including: a case having an accommodation space in a tubularinterior; and an electrode body disposed in the accommodation space inthe case, and including a positive plate, a negative plate, and aseparator disposed between the positive plate and the negative plate. Aspacer formed of a dense body and an electrolyte storage space in whichan electrolyte is stored are provided between the electrode body and thecase on one end or both ends of the case in an axial direction of theelectrode body.

With this configuration, an electrode group shorten in the axialdirection of the battery case is used, so that a battery at low costscan be provided. Moreover, even though the separator is excessivelyimpregnated with an electrolyte in order to prolong a battery life andthe electrolyte overflows from the electrode group, the electrolyte canbe stored in the electrolyte storage space. Furthermore, an internalpressure increase in the battery can be relaxed because the electrolytestorage space is provided, and a battery of high energy density and along life can be provided.

In addition, in the case where the battery is laterally disposed, whenthe electrolyte included in the separator is decreased, the overflownelectrolyte stored in the electrolyte storage space is again absorbed inthe separator because of a capillary action or the like, so that aninternal resistance increase in the battery due to the drying up of thesolution in the separator can be prevented, and a battery of a longerlife can be provided. Moreover, a dense body is used for the spacer toprovide a spacer of high strength. The spacer supports the electrolytestorage space, so that it can be prevented that the space is deformeddue to an external force or the like.

In the battery according to this aspect, the electrode body may bedisposed close to a positive electrode terminal formed on one end faceof the battery case; and the electrolyte storage space may be formed onan opposite side of the positive electrode terminal side of theelectrode body.

Thus, a distance between the positive electrode terminal and theelectrode group provided on the battery case can be shortened, and anelectrical resistance increase and a discharge efficiency decrease canbe prevented in connecting the positive electrode terminal to theelectrode group.

In the battery according to this aspect, the spacer may be disposed inthe electrolyte storage space with a gap; one end of the spacer maycontact a part of one end face of the electrode body in an axialdirection; and other end of the spacer may contact one end face of thebattery case to fix the electrode body so that the electrode body is notmoved in the axial direction.

Thus, it can be prevented that the electrode group enters theelectrolyte storage space, and the occurrence of a short circuit can beprevented, which is caused by the movement of the electrode group in theaxial direction to electrically disconnect the positive electrodeterminal. Moreover, a gap is provided between the battery case and theelectrode group even though the spacer is disposed, so that theelectrolyte overflowing from the electrode group can be stored in theelectrolyte storage space without being obstructed by the spacer.

In the battery according to this aspect, the spacer may be formed of aplurality of plate members disposed as erected in an axial direction ofthe battery case.

Thus, in the case where the electrode group has a wound structure inwhich the positive plate, the negative plate, and the separator arewound in a coiled shape, the winding displacement of the electrode groupcan be prevented by contacting one end face of the electrode group withone ends of the plurality of plate members. Moreover, the plate membersare disposed in the battery case as erected, so that it can be preventedthat the electrolyte storage space is greatly narrowed because thespacer is disposed.

In the battery according to this aspect, the spacer may be formed of acolumnar member.

Thus, the spacer can be easily manufactured by cutting a columnar rodmember having a certain length in the axial direction at a desiredposition. Moreover, when a hollow space is provided in the columnarmember, the region of the electrolyte storage space can be provided muchwider than in a solid member.

In the battery according to this aspect, the spacer may have elasticityin the axial direction of the battery case, and dimensions in the axialdirection may be deformable.

Thus, even though the battery is vibrated in the axial direction inorder to again impregnate the separator with the electrolyte stored inthe electrolyte storage space, the occurrence of a short circuit causedby the movement of the electrode group and the displacement of theelectrode group caused by vibrations can be prevented because the spacerserves as a spring.

According to another aspect of the present invention, there is provideda battery including: a case having an accommodation space in the case;and an electrode body disposed in the accommodation space in the case,and including a plurality of electrode plates having an active materiallayer including an active material and a substrate, and separator. Atleast one of the electrode plates has an active material layer formingportion in which the active material layer is formed on the substrateand a non-active material layer forming portion in which the activematerial layer is not formed. At least the non-active material layerforming portion contacts an inner wall of the case.

With the battery according to this aspect, at least one of the pluralityof electrode plates is configured to include the active material layerforming portion and the non-active material layer forming portion, sothat the amount of the active material coated, that is, the amount ofelectrodes used can be decreased as compared with a configuration inwhich the non-active material layer forming portion is not provided.Moreover, the unsteadiness of the electrode body in the case can besuppressed as compared with a configuration in which the electrode plateis formed while the substrate is made shorter.

In the battery according to this aspect, the electrode body may have apair of the non-active material layer forming portions on both ends ofthe electrode body; and the active material layer forming portion may beprovided between the pair of the non-active material layer formingportions.

With the battery according to this aspect, the width of the activematerial layer forming portion in one direction, that is, fabricationerrors in the width of the region functioning as an electrode can besuppressed as compared with a configuration in which the active materiallayer forming portion is provided on both ends of the electrode body.

In the battery according to this aspect, the plurality of electrodeplates may be configured by a positive plate and a negative plate; theseparator may be disposed between the positive plate and the negativeplate; and both of the positive plate and the negative plate may includethe active material layer forming portion and the non-active materiallayer forming portion.

With the battery according to this aspect, the configuration is providedin which the non-active material layer forming portion is formed on bothof the positive plate and the negative plate, so that the amount of theactive material coated can be further decreased as compared with aconfiguration in which the non-active material layer forming portion isnot formed.

In the battery according to this aspect, the substrate may be a porousbody.

With the battery according to this aspect, a porous body is used for thesubstrate, so that a weight reduction in the battery can be achievedwhile suppressing the unsteadiness of the electrode body as comparedwith a configuration in which a non-porous metal plate is used for thesubstrate.

According to still another aspect of the present invention, there isprovided a battery including: a tubular case; and an electrode bodyhaving a positive plate and a negative plate wound with a separatorinterposed therebetween. The electrode body is accommodated in the case,and includes a spacer on both ends of the electrode body in a windingaxial direction. At least a part of an outer circumferential portion ofthe spacer contacts an inner wall surface of the case.

With the battery according to this aspect, the amount of electrodes usedwith respect to the accommodation space in the case can be decreased ascompared with a configuration in which the electrode body is formedacross the overall length of the accommodation space in the case.

In the battery according to this aspect, the outer circumferentialportion of the spacer may contact the inner wall surface in a directionalong a direction in which a pair of closing portions are opposite toeach other in the case in a half of a length of a circumference of theinner wall surface or more.

With the battery according to this aspect, the distortion of the casecan be suppressed while suppressing the unsteadiness of the electrodebody.

In the battery according to this aspect, at least one of the spacers maycontinuously contact a half of the inner wall surface of the case ormore.

With the battery according to this aspect, the distortion of the casecan be further suppressed as compared with a configuration in which thespacer intermittently contacts a half or more of the inner wall surfaceof the case.

In the battery according to this aspect, at least one of the spacers mayhave a ring shape and may contact all around the inner wall surface inthe length of the circumference in a circumferential direction.

With the battery according to this aspect, a reduction in the spacerstrength can be suppressed while suppressing the amounts of thematerials to form the spacer as compared with a configuration in whichat least one of the spacers is a solid body with no hollow portion, forexample.

According to yet another aspect of the present invention, there isprovided a battery including: a battery case including a tubular portionhaving an accommodation space in the tubular portion; an electrode bodyaccommodated in the accommodation space, including a positive plate, anegative plate, and a separator disposed between the positive plate andthe negative plate, the positive plate, the negative plate, and theseparator being disposed as contacting an inner face of the tubularportion along the inner face of the tubular portion, the electrode bodyincluding a tubular hollow portion; and a spacer accommodated in thehollow portion and contacting an inner circumferential face of theelectrode body.

With this configuration, the electrode body is wound around the hollowportion, so that the amount of electrodes used can be decreased ascompared with the case where the electrode body is wound with no hollowportion.

Moreover, the spacer is accommodated in the hollow portion to contactthe inner circumferential face of the electrode body, and the outercircumferential face on the opposite side of the inner circumferentialface on the hollow portion side of the electrode body contacts the innerface of the tubular portion, so that the electrode body can be supportedby the spacer from the inner side, and can be externally supported bythe tubular portion. Thus, the unsteadiness of the electrode body in thebattery case can be suppressed. Accordingly, the amount of electrodesused can be decreased while suppressing the unsteadiness of theelectrode body in the battery case.

In the battery according to this aspect, the spacer may press theelectrode body to the tubular portion side.

With this configuration, force to support the electrode body by thespacer in the tubular portion can be improved. Moreover, a distancebetween the electrodes can be decreased, so that the input/outputresistance of the battery can be decreased.

In the battery according to this aspect, the spacer may be formed of anelastic body.

With this configuration, the electrode body can be positioned bypressing the electrode body to the inner face side of the tubularportion using the elastic force of the spacer.

In the battery according to this aspect, the spacer may contact allaround the inner circumferential face of the electrode body.

With this configuration, the unsteadiness of the electrode body in thebattery case can be further suppressed.

In the battery according to this aspect, the battery case may be ofconductivity; the negative plate may be disposed on at least a part ofan outer face of the electrode body; and the negative plate of the outerface may contact the inner face of the tubular portion.

With this configuration, the negative plate of the electrode body can beelectrically connected to the battery case.

According to yet another aspect of the present invention, there isprovided a battery including: a conductive battery case; a cylindricalelectrode body accommodated in the battery case and including a positiveplate, a negative plate, and a separator disposed between the positiveplate and the negative plate, the cylindrical electrode body including adiameter reducing portion whose outer diameter is smaller than an innerdiameter of the battery case; and a conductive spacer disposed betweenan outer circumferential face of the diameter reducing portion and aninner face of the battery case to electrically connect the cylindricalelectrode body to the battery case.

With this configuration, the amount of electrodes used can be decreasedas compared with the case where the cylindrical electrode body does notinclude the diameter reducing portion whose outer diameter is smallerthan the inner diameter of the battery case. Moreover, the spacer isdisposed between the outer circumferential face of the diameter reducingportion and the inner face of the battery case, so that the unsteadinessof the cylindrical electrode body in the battery case can be suppressed.

Accordingly, the amount of electrodes used can be decreased whilesuppressing the unsteadiness of the electrode body in the battery case.

Furthermore, the spacer electrically connects the cylindrical electrodebody to the battery case, so that the spacer for preventing theunsteadiness of the cylindrical electrode body can be used forelectrical connection between the cylindrical electrode body and thebattery case.

In the battery according to this aspect, an outer circumferential faceof the cylindrical electrode body may be electrically connected to theinner face of the battery case only through the spacer.

In the battery according to this aspect, the spacer may be disposed on amiddle portion of the cylindrical electrode body in an axial direction.

With this configuration, the deformation of the middle portion of thecylindrical electrode body in the axial direction can be prevented. Themiddle portion is relatively prone to be deformed.

In the battery according to this aspect, the negative plate may bedisposed at least on an outer face of the cylindrical electrode body;and the negative plate of the outer face of the cylindrical electrodebody may contact the spacer.

With this configuration, the configuration can be simplified as comparedwith a configuration in which for example, the lead wire is used toelectrically connect the negative plate to the spacer.

The spacer may be made of a metal braided in a mesh form.

With this configuration, the shape of the spacer can be deformed, sothat the accommodation of the spacer into the battery case can befacilitated.

The spacer may be made of a wire material in a coil form.

With this configuration, manufacturing costs can be decreased ascompared with the case where a mold or the like is used to shape theshape of the spacer.

The spacer may entirely surround an outer circumferential portion of thediameter reducing portion.

With this configuration, the deformation of the cylindrical electrodebody caused by locally and externally applying force from the spacer tothe cylindrical electrode body can be suppressed, and the contact areabetween the cylindrical electrode body and the spacer can be increased,so that electrical resistance between the cylindrical electrode body andthe battery case can be decreased.

In the battery according to this aspect, an electrolyte storage spacemay be provided between the outer face of the cylindrical electrode bodyand the inner face of the battery case.

With this configuration, even though the separator is excessivelyimpregnated with an electrolyte in order to prolong a battery life andthe electrolyte overflows from the electrode body, the electrolyte canbe stored in the electrolyte storage space. Moreover, an internalpressure increase in the battery can be relaxed because the electrolytestorage space is provided, and a battery of high energy density and along life can be provided.

Furthermore, when the battery is tilted and the electrolyte included inthe separator is decreased, the overflown electrolyte stored in theelectrolyte storage space is again absorbed in the separator because ofa capillary action or the like, so that an internal resistance increasein the battery due to the liquid shortage of the separator can beprevented, and a battery of a longer life can be provided.

According to yet another aspect of the present invention, there isprovided a battery including: a battery case including a tubularportion; a cylindrical electrode body including a positive plate, anegative plate, and a separator disposed between the positive plate andthe negative plate, the cylindrical electrode body including a diameterreducing portion whose outer diameter is smaller than an inner diameterof the tubular portion; and a spacer disposed between the tubularportion and the cylindrical electrode body, the spacer contacting aninner face of the tubular portion and an outer face of the cylindricalelectrode body. The cylindrical electrode body in the tubular portion isdisposed at a position at which an axis of the cylindrical electrodebody is different from an axis of the tubular portion.

With this configuration, the outer diameter of the cylindrical electrodebody is smaller than the inner diameter of the battery case, so that theamount of electrodes used can be decreased as compared with the casewhere the cylindrical electrode body having the same size as the innerdiameter of the battery case is used, for example. Moreover, the spacercontacts the outer face of the cylindrical electrode body and the innerface of the battery case, so that the unsteadiness of the cylindricalelectrode body in the battery case can be suppressed.

Accordingly, the amount of electrodes used can be decreased whilesuppressing the unsteadiness of the electrode body in the battery case.

Furthermore, the cylindrical electrode body in the tubular portion isdisposed at a position at which the axis of the cylindrical electrodebody is different from the axis of the tubular portion, so that thespacer can be disposed closer to the axis of the tubular portion in thebattery case, and the degree of freedom of the disposition of the spacercan be improved.

In the battery according to this aspect, the outer face of thecylindrical electrode body may contact the inner face of the tubularportion.

With this configuration, at least one side of the cylindrical electrodebody can be supported by the tubular portion, so that the unsteadinessof the cylindrical electrode body in the battery case can be suppressed.

In the battery according to this aspect, the battery case may be ofconductivity; the negative plate may be disposed at least on a part ofan outer face of the cylindrical electrode body; and the negative plateof the outer face may contact the inner face of the tubular portion.

With this configuration, the negative plate of the cylindrical electrodebody can be electrically connected to the battery case.

In the battery according to this aspect, a length of the cylindricalelectrode body in an axial direction may be a length across an overalllength of the accommodation space in a direction along the axialdirection; and the spacer may have a length across an overall length ofthe cylindrical electrode body in an axial direction.

With this configuration, the unsteadiness of the electrode body in thebattery case can be more reliably prevented.

According to yet another aspect of the present invention, there isprovided a battery including: a case having an accommodation space inthe case; and an electrode body disposed in the accommodation space inthe case and including a plurality of electrode plates having an activematerial layer including an active material and a substrate, andseparator. At least one of the plurality of electrode plates or theseparator includes a wide width portion and a narrow width portion whosewidths are different from each other in a direction vertical to alongitudinal direction of the electrode body or the separator.

With the battery according to this aspect, the amount of electrodes usedwith respect to the accommodation space in the case can be decreasedwhile suppressing the unsteadiness of the electrode body in the case, orthe amounts of materials to form the electrode body can be suppressed ascompared with a configuration in which the widths of the electrode plateand the separator are uniform. Moreover, the amounts of materials toform the electrode body can be decreased, so that the weight of thebattery can be reduced.

In the battery according to this aspect, any of the plurality ofelectrode plates may include the wide width portion and the narrow widthportion whose widths are different from each other.

With the battery according to this aspect, the amount of electrodes usedcan be decreased while holding the electrolyte in the separator ascompared with a configuration in which only one of the plurality ofelectrode plates includes the wide width portion and the narrow widthportion whose widths are different from each other, and the strength canbe further provided on locations to contact.

In the battery according to this aspect, the plurality of electrodeplates may be configured by a positive plate and a negative plate; theelectrode body may be configured such that the positive plate, thenegative plate, and the separator are wound as an axis along thelongitudinal direction is in a center; in the electrode body, a centerportion wound at a position close to the axis may be the wide widthportion; and in the electrode body, a peripheral portion wound aroundthe center portion may be the narrow width portion.

With the battery according to this aspect, the used amount of the metalplate can be suppressed as compared with a configuration in which thecenter portion is the narrow width portion and the peripheral portion isthe wide width portion.

In the battery according to this aspect, the separator may include thewide width portion and the narrow width portion; and in the longitudinaldirection, the width of the narrow width portion of the plurality ofelectrode plates and at least a part of the width of the narrow widthportion of the separator may have same lengths.

With the battery according to this aspect, the position can be adjustedin the narrow width portion in the state in which the electrode plate isopposite to the separator, and the electrode plate can be more easilymanufactured.

In the battery according to this aspect, the active material may becoated on the narrow width portion; and the active material may not becoated on the wide width portion.

With the battery according to this aspect, the amount of electrodes usedcan be further decreased as compared with a configuration in which theactive material is coated on both of the narrow width portion and thewide width portion.

It is noted that preferably, the battery according to the presentinvention is a nickel-metal hydride rechargeable cell in which thepositive plate has nickel hydroxide as a positive active material; andthe negative plate has a hydrogen storage alloy as a negative activematerial.

First Aspect First Embodiment

A first embodiment in a first aspect of the present invention will bedescribed below with reference to FIGS. 1 to 5. A battery 1 according tothis embodiment is an alkaline secondary battery such as a nickel-metalhydride rechargeable cell. Specifically, the battery 1 is a low capacitytype such as an AA battery having a capacity of 1800 mAh or less and anAAA battery having a capacity of 650 mAh or less, for example.

The battery 1 according to this embodiment is configured by a metalbattery case 2 having a nickel-plated surface and an electrode group 3disposed in the battery case 2.

As shown in FIG. 1, the battery case 2 is configured by a battery casemain body 2 a having a cylindrical shape with a bottom in which one endis opened and the other end is closed and a cover 2 b that closes theopening of the battery case main body 2 a through an insulator. Thebattery case main body 2 a becomes a negative electrode terminal of thebattery 1 by contacting a negative plate 3 c, described later. Moreover,the cover 2 b becomes the positive electrode terminal of the battery 1by contacting a positive plate 3 a, described later, through an elasticconnecting terminal 4.

The electrode group 3 is disposed in such a way that the electrode group3 is adjacent to the cover 2 b in the battery case main body 2 a, andincludes the positive plate 3 a, the negative plate 3 c, and a separator3 b disposed between them and including an electrolyte. It is noted thatin this embodiment, the electrode group 3 has a cylindrical shape inwhich the positive plate 3 a, the negative plate 3 c, and the separator3 b are wound in a coiled shape. Alternatively, the electrode group 3may have a rectangular shape in which the positive plate 3 a, thenegative plate 3 c, and the separator 3 b are stacked on each other.

The positive plate 3 a is a plate that a mixture of a nickel hydroxideactive material and a conductive cobalt compound is filled in hollowspaces of a positive electrode substrate made of nickel foam. It isnoted that the nickel hydroxide active material is nickel hydroxide, forexample, in the case of a nickel-cadmium rechargeable cell, whereas thenickel hydroxide active material is nickel hydroxide added with calciumhydroxide, for example, in the case of a nickel-metal hydriderechargeable cell.

The negative plate 3 c includes a negative current collector formed of aflat, nickel-plated steel sheet with punched holes, for example, and anegative active material coated on the negative current collector. It isnoted that the negative active material is a mixture of cadmium oxidepowder and metal cadmium powder, for example, in the case of anickel-cadmium rechargeable cell, whereas the negative active materialis hydrogen storage alloy powder mainly of AB5 type (rare earth-Ni),AB3.0-3.8 type (rare earth-Mg—Ni), or AB2 type (Laves phase), forexample, in the case of a nickel-metal hydride rechargeable cell.

The separator 3 b is made of polyolefin nonwoven fabric, for example,and the separator 3 b is impregnated with an electrolyte containingprimarily potassium hydroxide or sodium hydroxide.

As shown in FIG. 1, the battery 1 according to this embodiment isconfigured such that the length of the electrode group 3 is shortened inthe axial direction of the battery case 2 (hereinafter, noted as theaxial direction), an electrolyte storage space 6 is provided on theopposite side of the positive electrode terminal side of the battery 1for storing an electrolyte, and a spacer 5 is disposed in theelectrolyte storage space 6.

The spacer 5 is a dense body, and made of a resin that does not reactwith an electrolyte such as an acrylic resin, a polypropylene resin, anda nylon resin, or a material such as stainless steel, and the spacer 5is disposed in such a way that one end contacts a part of one end faceclosed of the battery case main body 2 a and the other end contacts apart of one end face of the electrode group 3. Thus, since theconnecting terminal 4 is disposed on the positive electrode terminalside and the spacer 5 is disposed on the opposite side of the positiveelectrode terminal side, the electrode group 3 is fixed to the batterycase 2 as the both ends of the electrode group 3 are sandwiched in theaxial direction. It is noted herein that the dense body may be a densebody whose porosity is 0 to 10% in a frame shape. Since a frame-shapeddense body can secure spacer strength when a member configuring theframe is a dense body, the dense body makes a spacer formed of the densebody.

Moreover, as shown in FIG. 2, the spacer 5 is configured such that threeplate members 5 a are disposed as erected at equal angles (120°) witheach other as the axis of the battery case 2 is in the center, one endsof the plate members 5 a are joined in the center, and the plate members5 a are integrally shaped. The length of the spacer 5 in the axialdirection is formed in the same length as the distance from one end faceof the battery case main body 2 a to one end face of the electrode group3.

It is noted that as shown in FIG. 3, the spacer 5 may be configured byfour plate members 5 a deposed as erected at equal angles (90°) witheach other as the axis of the battery case 2 is in the center.

Alternatively, the spacer 5 may be configured such that the spacer 5 haselasticity in the axial direction and dimensions are changeable in theaxial direction. For example, the spacer 5 may be configured such thatone end of the plate member 5 a contacting the electrode group 3 ishelically positioned to the other end of the plate member 5 a contactingthe battery case 2 as shown in FIG. 4, or may be configured such thatthe spacer 5 is formed in a spring shape as shown in FIG. 5.

The electrolyte storage space 6 is a space provided between theelectrode group 3 and the battery case main body 2 a, and the spacer 5is disposed in a part of the space. Since the spacer 5 contacts only apart of the electrode group 3, an electrolyte overflowing from theelectrode group 3 is guided to and stored in the space without beingobstructed by the spacer 5.

In the battery 1 according to this embodiment, the electrode group 3whose length is shortened in the axial direction of the battery case 2is used, so that a battery at low costs can be provided. Moreover, eventhough the separator 3 b is excessively impregnated with an electrolytein order to increase energy density and to prolong a battery life, theelectrolyte overflowing from the electrode group 3 can be stored in theelectrolyte storage space 6. Furthermore, an internal pressure increasein the battery 1 can be relaxed because the electrolyte storage space 6is provided, and the battery 1 of high energy density and a long lifecan be provided.

In addition, in the case where the battery 1 according to thisembodiment is laterally disposed, the overflown electrolyte stored inthe electrolyte storage space 6 is again absorbed in the separator 3 bbecause of a capillary action or the like when the electrolyte includedin the separator 3 b is decreased, so that an internal resistanceincrease in the battery 1 due to the drying up of the solution in theseparator 3 b can be prevented, and the battery 1 of a longer life canbe provided.

Moreover, in the battery 1 according to this embodiment, the electrodegroup 3 is disposed close to the cover 2 b (the positive electrodeterminal), and the electrolyte storage space 6 is formed between theelectrode group 3 and the battery case main body 2 a and provided on theopposite side of the positive electrode terminal side, so that adistance between the positive electrode terminal and the electrode group3 provided in the battery case 2 can be shortened, and an electricalresistance increase and a discharge efficiency decrease can be preventedin connecting the positive electrode terminal to the electrode group 3.

The battery 1 according to this embodiment includes the spacer 5disposed in the electrolyte storage space 6 with a gap, one end contactsa part of one end face of the electrode group 3 in the axial direction,the other end contacts one end face of the battery case 2, and thespacer 5 fixes the electrode group 3 in no movement in the axialdirection. Thus, it can be prevented that the electrode group 3 entersthe electrolyte storage space 6, and the occurrence of a short circuitcan be prevented, which is caused by the movement of the electrode group3 in the axial direction to electrically disconnect the positiveelectrode terminal. Moreover, a gap is provided between the battery case2 and the electrode group 3 even though the spacer 5 is disposed, sothat an electrolyte overflowing from the electrode group 3 can be storedin the electrolyte storage space 6 without being obstructed by thespacer 5.

Furthermore, the spacer 5 is disposed as erected in the axial direction.In the case where the electrode group 3 has a wound structure in whichthe positive plate 3 a, the negative plate 3 c, and the separator 3 bare wound in a coiled shape, winding displacement in the electrode group3 can be prevented by contacting one end face of the electrode group 3with one ends of a plurality of the plate members 5 a. In addition, theplate members 5 a are disposed in the battery case 2 as the platemembers 5 a are erected, so that it can be prevented that theelectrolyte storage space 6 is greatly narrowed by disposing the spacer5.

Alternatively, the spacer 5 may be configured such that the spacer 5 haselasticity in the axial direction and dimensions are changeable in theaxial direction. With this configuration, even though the battery 1 isvibrated in the axial direction in order to again impregnate theseparator 3 b with the electrolyte stored in the electrolyte storagespace 6, the occurrence of a short circuit due to the movement of theelectrode group 3 and displacement in the electrode group 3 caused byvibrations, for example, can be prevented because the spacer 5 is bentto deform dimensions for serving as a spring.

Second Embodiment

Next, a second embodiment in the first aspect of the present inventionwill be described with reference to FIGS. 6 and 7. The battery 10according to this embodiment is different in the configuration of aspacer from the first embodiment. Since the other configurations aresimilar to the first embodiment, the description is omitted.

In this embodiment, in a battery case 2, a first spacer 11 is disposedon the positive electrode terminal side of an electrode group 3, and asecond spacer 12 is disposed on the opposite side of the positiveelectrode terminal side of the electrode group 3.

As shown in FIG. 7, the first spacer 11 has a disk shape in which a hole11 a is formed in the center part to dispose a connecting terminal 4. Asshown in FIG. 6, the first spacer 11 is disposed in such a way that oneend face contacts a battery case main body 2 a and the other end facecontacts the electrode group 3. It is noted that a plurality of holesmay be formed on the first spacer 11 other than the hole 11 a to disposethe connecting terminal 4.

As shown in FIG. 7, the second spacer 12 is configured by a disk 12 aformed with a hole in the center part and a plurality of plate members12 b integrally provided on one face of the disk 12 a and disposed aserected at equal angles as the axis of the battery case 2 is in thecenter. One face of the disk 12 a on which the plate members 12 b is notprovided contacts the electrode group 3, and the end face of the platemember 12 b is disposed so as to contact the battery case main body 2 a.

Both of the first spacer 11 and the second spacer 12 are made of a resinsuch as an acrylic resin, a polypropylene resin, and a nylon resin, or amaterial with rigidity such as stainless steel as similar to the firstembodiment. The electrode group 3 is fixed to the battery case 2 as theboth ends of the electrode group 3 are sandwiched in the axial directionbecause the first spacer 11 is disposed on the positive electrodeterminal side and the second spacer 12 is disposed on the opposite sideof the positive electrode terminal side.

An electrolyte storage space 6 is a space provided between the electrodegroup 3 and the battery case main body 2 a, and the first spacer 11 andthe second spacer 12 are disposed in a part of the space. Since thefirst spacer 11 and the second spacer 12 contact only a part of theelectrode group 3, an electrolyte overflowing from the electrode group 3is guided to and stored in the space without being obstructed by thefirst spacer 11 and the second spacer 12.

In the battery 10 according to this embodiment, the electrode group 3 isfixed as both end portions of the electrode group 3 in the axialdirection are sandwiched between the first spacer 11 and the secondspacer 12, so that the electrode group 3 is reliably fixed to thebattery case 2, and the occurrence of a short circuit caused by themovement of the electrode group 3 can be reliably prevented.

It is noted that the present invention is not limited to the first andthe second embodiments. The present invention is also applicable to asecondary battery such as a lithium ion secondary cell in addition to analkaline secondary battery, for example, or may be applied to a primarybattery.

Moreover, the spacer 5 according to the first and the second embodimentsmay be configured by columnar members 13 as shown in FIGS. 8A to 8C,FIGS. 9A to 9C, and FIGS. 10A to 10C. In these configurations, for thecolumnar shape, as shown in FIGS. 8A to 8C, FIGS. 9A to 9C, and FIGS.10A to 10C, the spacer 5 may be configured in a prism shape such as atriangular prism, a square prism, and a hexagonal prism, or the spacer 5may be configured in a cylindrical prism, not shown. Thus, the spacer 5can be easily manufactured by cutting the rod member having a columnarshape with a certain length in the axial direction at a desiredposition.

It is noted that, the columnar member 13 may have a hollow portion inthe columnar member 13 as shown in FIGS. 8A to 8C, or may be configuredby only a frame of the columnar member 13 as shown in FIGS. 9A to 9C.With this configuration, the area of the electrolyte storage space 6 canbe provided much wider than in a solid member. Moreover, the contactarea between the spacer 5 and a separator 3 b is made smaller than thecontact area of a solid member, so that in the case where the battery 1is laterally disposed, the overflown electrolyte stored in theelectrolyte storage space 6 can be easily and quickly absorbed in theseparator 3 b.

The present invention can be variously modified without departing fromthe scope of thereof.

Example 1

In the following, tests were conducted by comparing the battery 1according to the first embodiment with other batteries. The results areshown in Table 1.

<Test Materials>

Batteries of Samples 1 to 4 shown in Table 1 will be described below.Samples 1 to 4 are a nickel-metal hydride rechargeable cell. Morespecifically, a cylindrical metal case has internal dimensions with aheight of 42 mm and a diameter of 13.42 mm. An electrode group wound ina coil shape is accommodated in the metal case, 1.3 g (1.00 cc) of anelectrolyte containing a mixture of 4M potassium hydroxide, 3M sodiumhydroxide, and 0.8M lithium hydroxide is filled in the metal case, andthen the metal case is closed with a metal cover provided with a safetyvalve. Here, since the size and disposition manner of the electrodegroup are different in Samples 1 to 4, the different points will bedescribed below.

(Sample 1)

Sample 1 is the battery 1 according to the first embodiment, in whichthe spacer 5 is disposed on the bottom of a case, the spacer 5 is madeof a resin such as polypropylene, acrylic, polyethylene, and nylon or ametal such as stainless steel with a height of 21 mm and a thickness of0.5 mm, and the electrode group 3 with a height of 21 mm and a spaceinner diameter of 3 mm is disposed on the spacer 5, as shown in FIGS. 1and 2. The electrolyte storage space 6 is provided in a region in whichthe spacer 5 is disposed. One end of the electrode group 3 iselectrically connected to the positive electrode terminal provided onthe metal cover through the connecting terminal 4.

(Sample 2)

As shown in FIG. 11, in Sample 2, a filler 15 is disposed on the bottomof a case, the filler 15 has a circular cylindrical shape with a heightof 21 mm and a diameter of 13.42 mm and made of a resin such as epoxy,acrylic, polyethylene, and nylon or a metal such as stainless steel, andan electrode group 3 with a height of 21 mm and a space inner diameterof 3 mm is disposed on the filler 15.

(Sample 3)

Sample 3 is an embodiment of the present invention. As shown in FIG. 12,an electrode group 3 with a height of 21 mm and a space inner diameterof 3 mm is disposed on the bottom of a case. One end of the electrodegroup 3 is electrically connected to a positive electrode terminalprovided on the metal cover through a connecting terminal 40. Anelectrolyte storage space 6 is provided between the electrode group 3and the positive electrode terminal.

(Sample 4)

As shown in FIG. 13, in Sample 4, an electrode group 30 with a height of42 mm and a space inner diameter 7.62 mm is disposed in a case. Ascompared with the electrode group 3 in Samples 1 to 3, the electrodegroup 30 has a higher height, the number of turns of a positive plate, anegative plate, and a separator is decreased, and the space innerdiameter is larger.

(Method of Preparing Electrode Group)

It is noted that the electrode groups of Samples 1 to 4 weremanufactured by methods below.

(Method of Preparing Positive Plate)

For the active material of the positive plate, such an active materialwas used, in which 7 mass % of cobalt hydroxide was covered on thesurface of nickel hydroxide containing 3 mass % of zinc and 0.6 mass %of cobalt in a solid solution state. The positive electrode activematerial was mixed with an aqueous solution dissolved with a thickener(carboxymethyl cellulose) and 2 mass % of ytterbium oxide to prepare apaste. The paste was filled in nickel foam having a substrate arealdensity of 320 g/m² and dried, and the paste-filled nickel foam waspressed to have a porosity of 20%. The pressed nickel foam was cut intoa predetermined size, so that a positive plate having a positiveelectrode capacity of 1 Ah was prepared.

(Method of Preparing Negative Plate)

Hydrogen storage alloy powder (100 parts by mass) in the composition ofLa_(0.64)Pr_(0.20)Mg_(0.16)Ni_(3.45)Al_(0.15) ground in an average grainsize of D50=50 μm was added with an aqueous solution dissolved with athickener (methylcellulose). A paste was formed by adding 1 part by massof a binder (styrenebutadiene rubber), and the paste was applied on bothsides of a bored steel sheet (an aperture ratio of 50%) having athickness of 35 μm and dried. The sheet was pressed to have a porosityof 18%, and then cut into a predetermined size, so that a negative platehaving a negative electrode capacity of 1.3 Ah was prepared. Thepositive plate and the negative plate prepared by the methods were woundin a coil shape with a separator that is subjected to sulfonationinterposed therebetween, and an electrode group was prepared.

<Test Method>

The internal resistance values, the discharge capacity ratios, and theinternal pressure values of Samples 1 to 4 were measured by thefollowing method.

(Internal Resistance Value)

Terminals were contacted with the top cover and the bottom of the caseof Samples 1 to 4, and internal resistance values were measured using3560 High Tester made of Hioki E.E. Corporation.

(Discharge Capacity Ratio)

First, Samples 1 to 4 were placed under a measurement environment at atemperature of 20° C., and were charged at 0.1 ItA (100 mA) for 16hours. The charging was stopped for one hour, Samples 1 to 4 weredischarged to reach a voltage of 1 V at 0.2 ItA (200 mA), and adischarge capacity of 0.2 ItA in the discharging (hereinafter, alsoreferred to as a low rate capacity) was measured. Subsequently, Samples1 to 4 were placed under a measurement environment at a temperature of20° C., and were charged at 0.1 ItA (100 mA) for 16 hours. The chargingwas stopped for one hour, Samples 1 to 4 were discharged to reach avoltage of 1 V at 3 ItA (3000 mA), and a discharge capacity of 3 ItA inthe discharging (hereinafter, also referred to as a high rate capacity)was measured. Calculation of 3 ItA discharge capacity/0.2 ItA dischargecapacity×100 was performed using the results, and a discharge capacityratio of a high rate capacity to a low rate capacity was calculated.

(Internal Pressure Value)

A hole was bored in Samples 1 to 4, and a jig for internal pressuremeasurement was mound on the hole. Samples 1 to 4 were placed under ameasurement environment at a temperature of 20° C., and charged at 1 ItA(1000 mA) for 1.5 hours, and a maximum internal pressure in the chargingwas measured.

(Initial Formation)

It is noted that prior to conducting the tests, Samples 1 to 4 weresubjected to initial formation in accordance with the followingprocedures. First, Samples 1 to 4 were charged under an environment at atemperature of 20° C. at 0.1 ItA for 12 hours. Subsequently, Samples 1to 4 were discharged to reach a voltage of 1V at 0.2 ItA, and thisprocess was repeated for two cycles. Samples 1 to 4 were allowed tostand under an environment at a temperature of 40° C. for 48 hours.Samples 1 to 4 were charged under an environment at a temperature of 20°C. at 0.1 ItA for 16 hours. The charging was stopped for one hour, andSamples 1 to 4 were discharged to reach a voltage of 1V at 0.2 ItA. Thisprocess was repeated for three cycles, and then the formation wasfinished.

<Test Results>

TABLE 1 Discharge Capacity Ratio (3 ItA Discharge 0.2 ItA Capacity/0.2ItA Liquid Liquid Internal Discharge 3 ItA Discharge Discharge InternalAmount/ Amount/ Resistance/ Capacity/ Capacity/ Capacity × Pressure/ gcc mΩ mAh mAh 100)/% MPa Sample 1 1.3 1.00 40 1000 813 81.3 0.5 Sample 21.3 1.00 40 1000 803 80.3 0.8 Sample 3 1.3 1.00 51 995 801 80.5 0.6Sample 4 1.3 1.00 2000 0 0 0 Test was not conducted

Here, since it is difficult to conduct a test for the internal pressurein Sample 4 and it is difficult to compare the internal pressure withother samples, in the following, Sample 1, Sample 2, and Sample 3 willbe compared with each other.

In the comparison of Sample 1 and Sample 3 with Sample 2, Samples 1 and3 have a greater discharge capacity ratio and have a smaller internalpressure value than in Sample 2. This can be considered that an increasein the internal pressure in the battery was suppressed and the dischargecapacity ratio was increased because Samples 1 to 3 are provided withthe electrolyte storage space. Thus, the battery provided with theelectrolyte storage space can prevent an increase in the internalpressure and is of high capacity as compared with a battery with noelectrolyte storage space.

Moreover, in the comparison of Sample 1 with Sample 3, Sample 1 has asmaller internal resistance value and a greater discharge capacity ratiothan in Sample 3. This can be considered that an electrical resistanceincrease and a discharge efficiency decrease were suppressed to decreasethe internal resistance value and the discharge capacity ratio wasincreased because Sample 1 has a shorter distance between the electrodegroup and the positive electrode terminal than in Sample 3. Thus, ashorter distance between the electrode group and the positive electrodeterminal is preferable to obtain a battery that can prevent an internalresistance increase and is of high capacity.

Example 2

Next, tests were conducted to change the amount of an electrolyte withwhich the separator 3 b is impregnated using the battery 1 according tothe first embodiment. The results are shown in Table 2.

<Test Materials>

Sample 1 and Samples 5 to 8 are the nickel-metal hydride rechargeablecell 1 according to the first embodiment. More specifically, as shown inFIGS. 1 and 2, the spacer 5 is disposed on the bottom of the cylindricalmetal case and the electrode group 3 is disposed on the spacer 5. Anelectrolyte containing a mixture of 4M potassium hydroxide, 3M sodiumhydroxide, and 0.8 M lithium hydroxide is filled in the case in apredetermined amount shown in Table 2 for every sample, and then themetal case is closed with a metal cover provided with a safety valve.Here, since the amount per unit positive electrode capacity of anelectrolyte contained in the separator of a typical battery ranges from0.8 to 1 cc/Ah, Samples 6 to 8 include an excessive electrolyte morethan usual. It is noted that since Sample 1 is the same as Sample 1 inTable 1, and the internal dimensions of the case of Sample 1 and Samples5 to 8 and the materials of the spacer 5, the electrode group and thelike of Sample 1 and Samples 5 to 8 are the same as the test materialsof Example 1, the description is omitted here.

<Test Method>

The discharge capacity ratios and internal pressure values of Sample 1and Samples 5 to 8 were measured. It is noted that since the test methodor the method of initial formation are the same as the test method inExample 1, the description is omitted here.

<Test Results>

TABLE 2 Discharge Capacity Ratio (3 ItA Discharge Positive 0.2 ItACapacity/0.2 ItA Liquid Electrode Discharge 3 ItA Discharge DischargeInternal Amount/ Capacity/ Capacity/ Capacity/ Capacity × Pressure/ ccAh cc/Ah mAh mAh 100)/% MPa Sample 5 0.77 1 0.77 970 146 15 0.4 Sample 11 1 1 1000 813 81.3 0.5 Sample 6 1.53 1 1.53 990 876 88.5 2 Sample 72.15 1 2.15 985 877 89 2.5 Sample 8 2.3 1 2.3 985 882 89.5 3.0 or more

As shown in Table 2, the discharge capacity ratio is increased as theliquid amount of the electrolyte included in the separator 3 b isincreased, and the internal pressure value is increased as well. Here,preferably, the battery has a lower internal pressure value. Morespecifically, an internal pressure value of 2.5 MPa or less ispreferable. However, in the battery 1 according to the first embodiment,the internal pressure value of the battery can be suppressed at aninternal pressure value of 2.5 MPa or less even though the amount of theelectrolyte included in the separator 3 b is increased more or less.Thus, in the battery provided with the electrolyte storage space, theleaked electrolyte can be stored in the electrolyte storage space eventhough the separator 3 b is excessively impregnated with an electrolytein order to prolong a battery life, so that an internal pressureincrease can be prevented, and a battery of high energy density and along life can be obtained.

Second Aspect

A battery 10 according to one embodiment in a second aspect of thepresent invention will be described with reference to FIGS. 14 to 19.The battery 10 is an alkaline secondary battery such as a nickel-metalhydride rechargeable cell. For example, the battery 10 is a low capacitytype such as an AA battery (“R6” in the IEC (InternationalElectrotechnical Commission), and “AA” in the United States) having acapacity of 1800 mAh or less, or an AAA battery (“R03” in the IEC, and“AAA” in the United States) having a capacity of 650 mAh or less. In thedescription below, the near side in FIG. 14 is the front side of thebattery 10, the right side of FIG. 14 is the right side of the battery10, and the upper side of FIG. 14 is the upper side of the battery 10.

As shown in FIG. 14, the battery 10 is configured by a battery case 11and an electrode body 23. The battery case 11 is made of a metal and hasa shape elongated in one direction. The battery case 11 is an example ofthe case, and configured by a battery case main body 12 and a cover 15,including an accommodation space S in the inside. It is noted that onedirection is a vertical direction in FIG. 14, the longitudinal directionof the battery case 11, and a direction opposite to the cover 15 and aclosing portion 14, described later.

The battery case main body 12 has a nickel-plated surface, and becomes anegative electrode terminal of the battery 10 by electrically connectinga negative plate 26, described later. The battery case main body 12 hasa shape in which one end is opened and the other end is closed in thevertical direction. More specifically, the battery case main body 12includes a tubular portion 13 and the closing portion 14.

The tubular portion 13 has a cylindrical shape elongated in the verticaldirection, and the shape of the inner circumferential face seen from thevertical direction is in a perfect circle in which an inner diameter Rpassing through a center axis W along the vertical direction isconstant. The inside of the tubular portion 13 is the accommodationspace S in which an electrode body 23, described later, can beaccommodated.

At one end of the tubular portion 13 in one direction, that is, at thetop end in FIG. 14, an opening 12A is formed to communicate with theinside of the tubular portion 13. The other end of the tubular portion13 in one direction, that is, the top end in FIG. 14 is closed with theclosing portion 14. The closing portion 14 is a circular plate member,and integrally formed with the tubular portion 13.

The cover 15 is electrically connected to a positive plate 24, describedlater, through an elastic connecting terminal 21, and becomes a positiveelectrode terminal of the battery 10. The cover 15 includes a cover mainbody 16, an elastic body 18, and a terminal plate 19. The cover mainbody 16 is a circular flat plate, made of a conductive material such asa nickel-plated iron material, for example, and electrically connectedto the positive plate 24 through the connecting terminal 21. A throughhole 17 is formed in the center part of the cover main body 16.

The elastic body 18 is disposed on the top face of the cover main body16, that is, on the other side of the face opposite to the closingportion 14 in such a way that the elastic body 18 blocks the throughhole 17. The elastic body 18 is made of a material such as rubber, forexample, and elastically deformed by an external force. The terminalplate 19 is a conductive plate covering the elastic body 18.

More specifically, the terminal plate 19 is electrically connected tothe cover main body 16 in the state in which the terminal plate 19presses the elastic body 18 downward, that is, the terminal plate 19presses the elastic body 18 against the cover main body 16. The terminalplate 19 is provided with a discharge hole 20 to emit a gas in thebattery case 11. For example, when the internal pressure of the batterycase 11 is increased and a pressure of a predetermined value or more isapplied to the elastic body 18 through the through hole 17, the elasticbody 18 is elastically deformed to communicate the inside of the batterycase 11 with the discharge hole 20, and a gas in the battery case 11 isdischarged to the outside of the battery 10 through the discharge hole20.

An elastically deformable insulator 22 is sandwiched between the opening12A of the battery case main body 12 and the cover 15 for sealing. Theinsulator 22 insulates the battery case main body 12 from the cover 15.

The electrode body 23 is accommodated in the accommodation space S inthe battery case 11. The electrode body 23 includes the positive plate24, the negative plate 26, and a separator 25 disposed between them andhaving an electrolyte, which are wound in a coiled shape as a windingaxis along the vertical direction is in the center. It is noted that thewinding axis may be matched with the center axis W or not. However, inthe following, for convenience of explanation, the winding axis ismatched with the center axis W.

It is noted that the inner diameter R of the tubular portion 13 issubstantially equal to an outer diameter L of the electrode body 23 (theouter diameter dimension in the lateral direction shown in FIG. 15).Thus, the electrode body 23 contacts an inner side face K (an example ofan inner wall) of the tubular portion 13. The inner side face K of thetubular portion 13 is a face along the vertical direction in the innerface of the battery case 11.

The separator 25 is made of polyolefin nonwoven fabric, for example. Theseparator 25 is impregnated with an electrolyte containing primarilypotassium hydroxide or sodium hydrate. The separator 25 is not disposedon a face opposite to the inner side face K of the tubular portion 13 inthe electrode body 23, and the negative plate 26, described later, isdisposed on the face opposite to the inner side face K of the tubularportion 13.

The positive plate 24 (an example of one electrode plate) is formed of apositive metal plate 24A (an example of the substrate) coated with apositive active material 24B (an example of the active material). Thepositive metal plate 24A is a porous body such as a perforated metal anda mesh body, and is made of nickel foam, for example. A porous body isused for the positive metal plate 24A, so that the weight of thepositive plate 24 can be decreased as compared with a configuration inwhich the porous body is not used. The positive active material 24B is amixture of a positive nickel hydroxide active material and a conductivecobalt compound. The positive plate 24 is formed in which the positiveactive material 24B is coated in hollow spaces in the positive metalplate 24A.

It is noted that in the case where the battery 10 is a nickel-cadmiumrechargeable cell, the positive active material 24B is made of nickelhydroxide, for example, and in the case where the battery 10 is anickel-metal hydride rechargeable cell, the positive active material 24Bis made of nickel hydroxide added with calcium hydroxide, for example.

The negative plate 26 (one of the other electrode plate) is formed ofthe negative metal plate 26A (an example of the substrate) coated withthe negative active material 26B (an example of the active material).The negative metal plate 26A is a porous body such as a perforatedmetal, a mesh body, a nickel-plated, and a flat bored steel sheet, forexample. A porous body is used for the negative metal plate 26A, so thatthe weight of the negative plate 26 can be decreased as compared with aconfiguration in which the porous body is not used. The negative activematerial 26B is powder such as cadmium powder and hydrogen storage alloypowder, for example. The negative plate 26 is formed of the negativemetal plate 26A coated with the negative active material 26B.

It is noted that the negative active material 26B is a mixture ofcadmium oxide powder and metal cadmium powder, for example, in the caseof a nickel-cadmium rechargeable cell, whereas the negative activematerial 26B is hydrogen storage alloy powder mainly of AB5 type (rareearth-Ni), AB3.0-3.8 type (rare earth-Mg—Ni), or AB2 type (Laves phase),for example, in the case of a nickel-metal hydride rechargeable cell.

Moreover, as shown in FIG. 16, in the upper part of the electrode body23 in the vertical direction, there is a region NF1 (an example of anon-active material layer forming portion) in which either the positiveactive material 24B or the negative active material 26B is not coatedacross the overall length in the winding direction of the electrode body23. Furthermore, in the lower part of the electrode body 23 in thevertical direction, there is a region NF2 (an example of a non-activematerial layer forming portion) in which either the positive activematerial 24B or the negative active material 26B is not coated acrossthe overall length in the winding direction of the electrode body 23. Itis noted that the region NF1 and the region NF2 have the same lengths inthe vertical direction.

In the center part of the electrode body 23 in the vertical direction,that is, in a portion sandwiched between the region NF1 and the regionNF2, there is a region TF (an example of an active material layerforming portion) of an active material layer coated with the negativeactive material 26B. It is noted that as described in detail in FIG. 19,there is a region TS (an example of an active material layer formingportion) of a combined martial coated with the positive active material24B across the overall length in the winding direction of the electrodebody 23 as opposite to the region TF.

FIG. 17 is a development view of the electrode body 23 unfolded. It isnoted that the vertical direction in FIG. 17 is the same as the verticaldirection in FIG. 16, and the lateral direction in FIG. 17 is the sameas the lateral direction in FIG. 16. In other words, FIG. 17 is a viewthat the electrode body 23 is unfolded and developed in the lateraldirection in FIG. 16.

As shown in FIG. 17, in the upper part of the positive metal plate 24Ain the vertical direction, there is a region NS1 (an example of anon-active material layer forming portion) in which the positive activematerial 24B is not coated in the lateral direction of the positivemetal plate 24A, that is, across the overall length in the windingdirection of the positive metal plate 24A. In the lower part of thepositive metal plate 24A in the vertical direction, there is a regionNS2 (an example of a non-active material layer forming portion) in whichthe positive active material 24B is not coated in the lateral directionof the positive metal plate 24A. It is noted that the region NS1 and theregion NS2 have the same lengths in the vertical direction.

In the center part of the positive metal plate 24A in the verticaldirection, that is, in a portion sandwiched between the region NS1 andthe region NS2, there is the region TS in which the positive activematerial 24B is coated in the lateral direction of the positive metalplate 24A. It is noted that as described above, there is the region TFin which the negative active material 26B is coated across the overalllength in the winding direction of the positive metal plate 24A asopposite to the region TS.

As shown in FIG. 18, in the case where the electrode body 23 ismanufactured, the positive metal plate 24A and the negative metal plate26A are wound in such a way that the region TS in which the positiveactive material 24B is coated on the positive metal plate 24A isdisposed opposite to the region TF in which the negative active material26B is coated on the negative metal plate 26A. Since the region TS inwhich the positive active material 24B is coated is disposed opposite tothe region TF in which the negative active material 26B is coated, acurrent is produced across the region TS and the region TF due to achemical reaction.

Since the region NS1 and the region NS2 in which the positive activematerial 24B is not coated are in the conductive positive metal plate24A, the current produced in the region TS is passed through thepositive metal plate 24A. Similarly, since the region NF1 and the regionNF2 in which the negative active material 26B is not coated are in theconductive negative metal plate 26A, the current produced in the regionTF is passed through the negative metal plate 26A.

Accordingly, the amount of electrodes used can be suppressed as comparedwith a configuration in which the active material is coated throughoutthe metal plate.

Effects of the Embodiment

According to this embodiment, the positive metal plate 24A has theregion TS in which the positive active material 24B is coated and theregion NS1 and the region NS2 in which the positive active material 24Bis not coated.

Moreover, the negative metal plate 26A has the region TF in which thenegative active material 26B is coated and the region NF1 and the regionNF2 in which the negative active material 26B is not coated.

In the electrode body 23, the positive metal plate 24A and the negativemetal plate 26A are wound in such a way that the region TS in which thepositive active material 24B is coated on the positive metal plate 24Ais disposed opposite to the region TF in which the negative activematerial 26B is coated on the negative metal plate 26A. Therefore, theamount of electrodes used can be suppressed as compared with aconfiguration in which the positive active material 24B is coatedthroughout the positive metal plate 24A and the negative active material26B is coated throughout the negative metal plate 26A.

Furthermore, the configuration is provided in which the positive activematerial 24B is partially coated on the positive metal plate 24A and thenegative active material 26B is partially coated on the negative metalplate 26A. Therefore, the unsteadiness of the electrode body 23 in thebattery case 11 can be suppressed as compared with a configuration inwhich the length of the positive metal plate 24A or the length of thenegative metal plate 26A in the vertical direction is shortened.

Other Embodiments

The techniques disclosed herein are not limited to the embodimentdescribed with reference to the drawings, and various forms below arealso included, for example.

In the embodiment above, an example is taken in which the electrode body23 has a cylindrical shape in which the positive plate 24, the negativeplate 26, and the separator 25 are wound counterclockwise as the centeraxis W is in the center. However, the embodiment is not limited thereto.Such a configuration may be possible in which the electrode body 23 isformed in a square shape in which a flat positive plate 24, a flatnegative plate 26, and a flat separator 25 are laid on each other toform a square shape as a whole, for example.

In the embodiment above, an example is taken in which the positiveactive material 24B is coated across the lateral direction of thepositive metal plate 24A and on the center part of the positive metalplate 24A in the vertical direction. However, the embodiment is notlimited thereto. The positive active material 24B may be partiallycoated in the lateral direction of the positive metal plate 24A.Moreover, the positive active material 24B may be coated only on theupper side of the positive metal plate 24A, or coated only on the lowerside, or coated on both of the upper side and the lower side, not on thecenter part of the positive metal plate 24A in the vertical direction.It is noted that as similar to the negative active material 26B, thenegative active material 26B may be coated only on the upper side of thenegative metal plate 26A, or coated only on the lower side, or coated onboth of the upper side and the lower side, not on the center part of thenegative metal plate 26A in the vertical direction.

In the embodiment above, the configuration is taken as an example inwhich the positive metal plate 24A has the region TS in which thepositive active material 24B is coated and the region NS1 and the regionNS2 in which the positive active material 24B is not coated, whereas thenegative metal plate 26A has the region TF in which the negative activematerial 26B is coated and the region NF1 and the region NF2 in whichthe negative active material 26B is not coated. However, the embodimentis not limited thereto. For example, such a configuration may bepossible in which the positive metal plate 24A has the region TS inwhich the positive active material 24B is coated and the region NS1 andthe region NS2 in which the positive active material 24B is not coated,whereas the negative metal plate 26A only has the region TF in which thenegative active material 26B is coated or vice versa.

Furthermore, such a configuration may be possible in which as shown inFIG. 19, the region NF1 is narrow in the vertical direction with respectto the region NS1, the region NF2 is narrow in the vertical directionwith respect to the region NS2, and the region TF is wide in thevertical direction with respect to the region TS, or vice versa. Inconfiguration in which the coated portion such as the region TS and theregion TF is provided at the end in one direction, when the metal plateis relatively displaced with respect to the position at which the activematerial is coated in the manufacturing steps of the battery 10, thewidth of the coated portion is increased or decreased in the directionof the winding axis. Therefore, the capacity of the battery 10 isincreased or decreased. Accordingly, the configurations above areprovided, so that fabrication errors in the width of the regionfunctioning as an electrode can be suppressed.

In the embodiment above, an example is taken in which the tubularportion 13 has a cylindrical shape. However, the embodiment is notlimited thereto. The tubular portion 13 may have a square shape.

In the embodiment above, the configuration is taken as an example inwhich the region NF1 and the region NF2 have the same lengths in thevertical direction. However, the embodiment is not limited thereto. Thelength of the region NF1 and the length of the region NF2 may bedifferent in the vertical direction. Moreover, in the embodiment above,the region NS1 and the region NS2 have the same lengths in the verticaldirection. However, the embodiment is not limited thereto. The length ofthe region NS1 and the length of the region NS2 may be different in thevertical direction.

In the embodiment above, an example is taken in which the positive metalplate 24A and the negative metal plate 26A are a porous body such as aperforated metal and a mesh body. However, the embodiment is not limitedthereto. The positive metal plate 24A and the negative metal plate 26Amay be a metal plate, not a porous body.

Third Aspect

A battery 10 according to one embodiment in a third aspect of thepresent invention will be described with reference to FIGS. 20 to 24.The battery 10 is an alkaline secondary battery such as a nickel-metalhydride rechargeable cell. For example, the battery 10 is a low capacitytype such as an AA battery (“R6” in the IEC (InternationalElectrotechnical Commission), and “AA” in the United States) having acapacity of 1800 mAh or less, or an AAA battery (“R03” in the IEC, and“AAA” in the United States) having a capacity of 650 mAh or less. In thedescription below, the near side in FIG. 20 is the front side of thebattery 10, the right side is the right side of the battery 10, and theupper side is the upper side of the battery 10.

As shown in FIG. 20, the battery 10 is configured by a battery case 11and an electrode body 23. The battery case 11 is made of a metal and hasa shape elongated in one direction. The battery case 11 is an example ofthe case, and configured by a battery case main body 12 and a cover 15(an example of a cover), including an accommodation space S in theinside. It is noted that one direction is a vertical direction in FIG.20, the longitudinal direction of the battery case 11, and a directionopposite to the cover 15 and a closing portion 14, described later.

The battery case main body 12 has a nickel-plated surface, and becomes anegative electrode terminal of the battery 10 by electrically connectinga negative plate 26, described later. The battery case main body 12 hasa shape in which one end is opened and the other end is closed in thevertical direction. More specifically, the battery case main body 12includes a tubular portion 13 and the closing portion 14.

The tubular portion 13 has a cylindrical shape elongated in the verticaldirection, and the shape of the inner circumferential face seen from thevertical direction is in a perfect circle in which an inner diameter Rfrom a center axis W along the vertical direction is constant. Theinside of the tubular portion 13 is the accommodation space S in whichan electrode body 23, described later, can be accommodated.

At one end of the tubular portion 13 in one direction, that is, at thetop end in FIG. 20, an opening 12A is formed to communicate with theinside of the tubular portion 13. The other end of the tubular portion13 in one direction, that is, the top end in FIG. 20 is closed with theclosing portion 14. The closing portion 14 is a circular plate member,and integrally formed with the tubular portion 13.

The cover 15 is electrically connected to a positive plate 24, describedlater, through an elastic connecting terminal 21, and becomes a positiveelectrode terminal of the battery 10. The cover 15 includes a cover mainbody 16, an elastic body 18, and a terminal plate 19. The cover mainbody 16 is a circular flat plate, made of a conductive material such asa nickel-plated iron material, for example, and electrically connectedto the positive plate 24 through the connecting terminal 21. A throughhole 17 is formed in the center part of the cover main body 16.

The elastic body 18 is disposed on the top face of the cover main body16, that is, on the other side of the face opposite to the closingportion 14 in such a way that the elastic body 18 blocks the throughhole 17. The elastic body 18 is made of a material such as rubber, forexample, and elastically deformed by an external force. The terminalplate 19 is a conductive plate covering the elastic body 18.

More specifically, the terminal plate 19 is electrically connected tothe cover main body 16 in the state in which the terminal plate 19presses the elastic body 18 downward, that is, presses the elastic body18 against the cover main body 16. The terminal plate 19 is providedwith a discharge hole 20 to emit a gas in the battery case 11. Forexample, when the internal pressure of the battery case 11 is increasedand a pressure of a predetermined value or more is applied to theelastic body 18 through the through hole 17, the elastic body 18 iselastically deformed to communicate the inside of the battery case 11with the discharge hole 20, and a gas in the battery case 11 isdischarged to the outside of the battery 10 through the discharge hole20.

An elastically deformable insulator 22 is sandwiched between the opening12A of the battery case main body 12 and the cover 15 for sealing. Theinsulator 22 insulates the battery case main body 12 from the cover 15.

The electrode body 23 is accommodated in the accommodation space S inthe battery case 11. The electrode body 23 includes the positive plate24, the negative plate 26, and a separator 25 disposed between them andhaving an electrolyte, which are wound in a coiled shape as a shaft M isin the center along the vertical direction. It is noted that the shaft Mmay be matched with the center axis W or not. However, in the following,for convenience of explanation, the shaft M is matched with the centeraxis W. An inner side face K of the tubular portion 13 is a face alongthe vertical direction in the inner face of the battery case 11. It isnoted that the electrode body 23 may be accommodated in theaccommodation space S in the state in which the shaft M is pulled out.

The electrode body 23 has a length V in the vertical direction, and thelength V is shorter than a length Y in the vertical direction of theaccommodation space S. A first spacer 27A and a second spacer 27B,described later, are disposed on the upper part and the lower part ofthe electrode body 23, respectively.

It is noted that the inner diameter R of the tubular portion 13 (aninner diameter dimension in the lateral direction in FIG. 21) issubstantially equal to an outer diameter L of the electrode body 23 (anouter diameter dimension in the lateral direction in FIG. 21).

The separator 25 is made of polyolefin nonwoven fabric, for example. Theseparator 25 is impregnated with an electrolyte containing primarilypotassium hydroxide or sodium hydrate. The separator 25 is not disposedon a face opposite to the inner side face K of the tubular portion 13 inthe electrode body 23, and the negative plate 26, described later, isdisposed on the face opposite to the inner side face K of the tubularportion 13.

The positive plate 24 is formed of the positive metal plate 24A (anexample of one metal plate) coated with the positive active material 24B(an example of an active material of one polarity). The positive metalplate 24A is made of nickel foam, for example. The positive activematerial 24B is a mixture of a positive nickel hydroxide active materialand a conductive cobalt compound. The positive plate 24 is formed inwhich the positive active material 24B is coated in hollow spaces in thepositive metal plate 24A.

It is noted that in the case where the battery 10 is a nickel-cadmiumrechargeable cell, the positive active material 24B is made of nickelhydroxide, for example, and in the case where the battery 10 is anickel-metal hydride rechargeable cell, the nickel hydroxide activematerial is nickel hydroxide added with calcium hydroxide, for example.

The negative plate 26 is formed of the negative metal plate 26A (anexample of the other electrode metal plate) coated with the negativeactive material 26B (an example of an active material of the otherpolarity). The negative metal plate 26A is a flat, nickel-plated boredsteel sheet, for example. The negative active material 26B is powdersuch as cadmium powder and hydrogen storage alloy powder (an example ofan active material of one polarity), for example. The negative plate 26is formed of the negative metal plate 26A coated with the negativeactive material 26B.

It is noted that the negative active material 26B is a mixture ofcadmium oxide powder and metal cadmium powder, for example, in the caseof a nickel-cadmium rechargeable cell, whereas the negative activematerial is hydrogen storage alloy powder mainly of AB5 type (rareearth-Ni), AB3.0-3.8 type (rare earth-Mg—Ni), or AB2 type (Laves phase),for example, in the case of a nickel-metal hydride rechargeable cell.

The first spacer 27A is disposed between the electrode body 23 and thecover 15. The first spacer 27A is a member that fixes the position ofthe tubular portion 13 of the electrode body 23 in the verticaldirection, or suppresses the deformation of the tubular portion 13 inthe longitudinal direction and the lateral direction.

The first spacer 27A is formed of a resin that does not react with anelectrolyte such as an acrylic resin, a polypropylene resin, and a nylonresin, or a material such as stainless steel. As shown in FIG. 22, thefirst spacer 27A is a ring-shaped member.

More specifically, the first spacer 27A has a length D in the verticaldirection, and has a cylindrical shape as a whole. An outer diameter Pof the first spacer 27A, that is, a long diameter in the diameter havingthe center axis W as the center is substantially equal to the innerdiameter R of the tubular portion 13. Therefore, the first spacer 27A isinserted into the tubular portion 13 with almost no gap. Since the firstspacer 27A has a ring shape, the first spacer 27A continuously contactsall around the inner side face K in the circumferential direction as thecenter axis W is in the center.

Moreover, an inner diameter Q of the first spacer 27A, that is, a shortdiameter in the diameter having the center axis W as the center isshorter than the outer diameter L of the electrode body 23. Therefore,the first spacer 27A contacts the electrode body 23 on the undersurface.

It is noted that the first spacer 27A and the second spacer 27B may havethe same functions, the same material, and the same shape. The secondspacer 27B is disposed between the electrode body 23 and the closingportion 14, and contacts the electrode body 23 on the top face.

As shown in FIG. 23, the diameter of the electrode body 23 has adiameter G1 passing through the end portion of the winding and adiameter G2 orthogonal to the diameter G1. Since the diameter G1 islonger than the diameter G2, the electrode body has an elliptical crosssection in the longitudinal direction and the lateral direction. Whenthe electrode body 23 is accommodated in the tubular portion 13 of thebattery 10 having a perfect circular shape while contacting the innerside face K, it is likely that the tubular portion 13 is deformed in anellipse as following the shape of the electrode body 23. Moreover, inthe case where the electrode body 23 repeatedly expands and contractsdue to the charging and discharging of the battery 10, it is likely thatthe deformation becomes noticeable.

The strength of the tubular portion 13 in the longitudinal direction andthe lateral direction is decreased from a portion BM near the closingportion 14 and a portion TP near the cover 15 toward a center part CR inthe vertical direction. Therefore, the portion BM near the closingportion 14 and the portion TP near the cover 15 in the tubular portion13 do not tend to be deformed even in the case where stress is appliedexternally and internally to the tubular portion 13. On the other hand,the portion near the center part CR is prone to be deformed in thetubular portion 13.

Therefore, in the case of the configuration in which the first spacer27A or the second spacer 27B is not provided, when stress is applied dueto the shape of the electrode body 23, for example, the tubular portion13 does not tend to be deformed at the portion BM near the closingportion 14 and the portion TP near the cover 15 in the tubular portion13 as indicated by solid lines in FIG. 24A, even though force acts inthe directions of arrows Y1. However, as indicated by dasheddouble-dotted lines in FIG. 24A, the electrode body 23, for example, isdeformed at the portion near the center part CR in the tubular portion13, and the tubular portion 13 is deformed in an ellipse, for example,when force acts in the directions of arrows Y1.

On the other hand, the configuration in which the first spacer 27A isprovided is a configuration in which the first spacer 27A contacts theinner side face K of the tubular portion 13 by the length D from theportion TP near the cover 15 in the vertical direction. Therefore, forthe inner side face K of the tubular portion 13 also contacting thefirst spacer 27A, a reduction in the strength in the longitudinaldirection and the lateral direction is suppressed through the firstspacer 27A, and the strength almost the same as the strength in theportion TP near the cover 15 is maintained.

As a result, as shown in FIG. 24B, even though force acts in thedirections of arrows Y1 because the electrode body 23 is to be deformed,the first spacer 27A causes force to act in the directions of arrows Y2in the directions opposite to the directions of the arrows Y1. With thisconfiguration, the deformation of the tubular portion 13 is suppressedalso at the portion near the center part CR in the tubular portion 13.

On the other hand, the configuration in which the second spacer 27B isprovided is a configuration in which the second spacer 27B contacts theinner side face K of the tubular portion 13 by the length D from theportion BM near the closing portion 14 in the vertical direction.Therefore, for the inner side face K of for the tubular portion 13 alsocontacting the second spacer 27B, a reduction in strength in thelongitudinal direction and the lateral direction is suppressed throughthe second spacer 27B, and the strength the same as the strength of theportion BM near the closing portion 14 is maintained.

As a result, as shown in FIG. 24B, even though force acts in thedirections of arrows Y1 because the electrode body 23 is to be deformed,the second spacer 27B causes force to act in the directions of arrows Y2in the directions opposite to the directions of the arrows Y1. With thisconfiguration, the deformation of the tubular portion 13 is suppressedalso at the portion near the center part CR in the tubular portion 13.

In other words, both of the first spacer 27A and the second spacer 27Bare provided, so that the deformation of the tubular portion 13 isfurther suppressed at the portion near the center part CR in the tubularportion 13.

Effects of the Embodiment

According to this embodiment, the electrode body 23 has the length V inthe vertical direction, and the length V is shorter than the length Y inthe vertical direction of the accommodation space S. Therefore, theamount of electrodes used with respect to the accommodation space S inthe battery case 11 can be decreased as compared with a configuration inwhich the electrode body 23 is formed across the overall length of theaccommodation space S in the battery case 11 in the vertical direction.

The specification of the battery 10 is defined as described above, andthe specification of the length of the battery case 11 in the verticaldirection (the overall length of the accommodation space S) is alsodefined. In this embodiment, the length of the electrode body 23 in thevertical direction is made shorter than the overall length of theaccommodation space S while maintaining the overall length of theaccommodation space S, which is not enabled to be changed, so that theamount of electrodes used can be decreased as the specification of anelectric power quantity is maintained.

Moreover, the first spacer 27A is disposed between the electrode body 23and the cover 15, and contacts the electrode body 23 on the undersurface, and the second spacer 27B is disposed between the electrodebody 23 and the closing portion 14, and contacts the electrode body 23on the top face. With this configuration, the unsteadiness of theelectrode body 23 in the battery case 11 can be suppressed as comparedwith a configuration in which the first spacer 27A and the second spacer27B are not provided in the battery case 11.

Furthermore, the configuration in which the first spacer 27A is providedis a configuration in which the first spacer 27A contacts the inner sideface K of the tubular portion 13 by the length D from the portion TPnear the cover 15 in the vertical direction. Therefore, for the innerside face K of the tubular portion 13 also contacting the first spacer27A, a reduction in the strength in the longitudinal direction and thelateral direction is suppressed through the first spacer 27A, and thestrength almost the same as the strength in the portion TP near thecover 15 is maintained.

The configuration in which the second spacer 27B is provided is aconfiguration in which the second spacer 27B contacts the inner sideface K of the tubular portion 13 by a length D from the portion BM nearthe closing portion 14 in the vertical direction. Therefore, for theinner side face K of for the tubular portion 13 also contacting thesecond spacer 27B, a reduction in strength in the longitudinal directionand the lateral direction is suppressed through the second spacer 27B,and the strength the same as the strength of the portion BM near theclosing portion 14 is maintained. Accordingly, the distortion of thebattery case 11 can be suppressed.

Other Embodiments

The techniques disclosed herein are not limited to the embodimentdescribed with reference to the drawings, and various forms below arealso included, for example.

In the embodiment above, an example is taken in which the electrode body23 has a cylindrical shape in which the positive plate 24, the negativeplate 26, and the separator 25 are wound counterclockwise. However, theembodiment is not limited thereto. Such a configuration may be possiblein which the electrode body 23 has a square shape as a whole in which aflat positive plate 24, a flat negative plate 26, and a flat separator25 are stacked on each other, for example.

In the embodiment above, an example is taken in which the first spacer27A and the second spacer 27B have a ring shape. However, the embodimentis not limited thereto. As shown in FIG. 25, the first spacer 27A andthe second spacer 27B may be a filled solid body. Moreover, the firstspacer 27A and the second spacer 27B may not have a perfect circularshape, or may have a semicircle or a two-thirds circle. Furthermore,such a configuration may be possible in which the first spacer 27A andthe second spacer 27B are in a form in which a plurality of platesradially extends from the center in a cross section in the longitudinaldirection and the lateral direction and a contacting portion between theplate and the inner side face K of the tubular portion 13 occupies ahalf or more in the circumferential direction in which the center axis Wis in the center. In short, the first spacer 27A and the second spacer27B may continuously contact or may intermittently contact the innerside face K of the tubular portion 13 when the first spacer 27A and thesecond spacer 27B contact a half or more of the inner side face K in thecircumferential direction in which the center axis W is in the center.

In the embodiment above, an example is taken in which the first spacer27A and the second spacer 27B have the same functions, the samematerial, and the same shape. However, the embodiment is not limitedthereto. The first spacer 27A and the second spacer 27B may be differentin all of the shape, the material, and the height, or may be differentin any one of them.

In the embodiment above, an example is taken in which the first spacer27A and the second spacer 27B are separate spacers. However, theembodiment is not limited thereto. The first spacer 27A and the secondspacer 27B may be integrally formed with each other. For example, thefirst spacer 27A and the second spacer 27B may be integrally formed witheach other through the hole (not shown) into which the shaft M isinserted.

In the embodiment above, an example is taken in which the tubularportion 13 has a cylindrical shape. However, the embodiment is notlimited thereto. The tubular portion 13 may have a square shape.

Fourth Aspect First Embodiment

A first embodiment in a fourth aspect of the present invention will bedescribed with reference to FIGS. 26 to 29.

A battery 10 according to this embodiment is an alkaline secondarybattery such as a nickel-metal hydride rechargeable cell. For example,the battery 10 is a low capacity type such as an AA battery (“R6” in theIEC (International Electrotechnical Commission), and “AA” in the UnitedStates) having a capacity of 1800 mAh or less and an AAA battery (“R03”in the IEC, and “AAA” in the United States) having a capacity of 650 mAhor less. Hereinafter, a description will be given for the verticaldirection and in the lateral direction with reference to the directionsshown in FIG. 27.

As shown in FIG. 26, the battery 10 includes a metal battery case 11, anelectrode body 23 accommodated in the battery case 11, and a spacer 27fit into the inner side of the electrode body 23 in the battery case 11.The battery case 11 is defined in the size according to thespecification. The battery case 11 has a shape elongated in the verticaldirection, has an accommodation space S in the inside, and has anickel-plated surface. The battery case 11 includes a cylindricalbattery case main body 12 with a bottom having an opening 12A opened atone end side and the other end closed, and a cover 15 that closes theopening 12A of the battery case main body 12.

The battery case main body 12 becomes a negative electrode terminal ofthe battery 10 by contacting the negative plate 26, described later, andincludes a tubular portion 13 and a closing portion 14 that closes thelower end of the tubular portion 13.

As shown in FIG. 27, the tubular portion 13 has a cylindrical shape, andthe inner circumferential portion and the outer circumferential portionof the tubular portion 13 have a perfect circle in which the diameterfrom an axis A passing through the center of the tubular portion 13 isconstant. The inside of the tubular portion 13 is the accommodationspace S in which an electrode body 23, described later, can beaccommodated, and an inner diameter B2 of the tubular portion 13 (thediameter of the inner face of the tubular portion 13 in the lateraldirection) is almost the same as the outer diameter of the electrodebody 23 (the diameter of the outer face of the electrode body 23 in thelateral direction).

To the upper end portion of the tubular portion 13, a diameter reducingportion 12B is connected. The diameter reducing portion 12B projects onthe inner side of the tubular portion 13 to reduce the inner diameter.The diameter reducing portion 12B partitions the top end of theaccommodation space S. On the diameter reducing portion 12B, a fittingportion 12C is formed into which the peripheral portion of the cover 15is fit through an insulator 22.

The closing portion 14 is formed of a circular plate member, andintegrally formed with the tubular portion 13.

The cover 15 is connected to a positive plate 24, described later,through an elastic connecting terminal 21, and becomes a positiveelectrode terminal of the battery 10. The cover 15 includes a flat covermain body 16, an exhaust valve 18 placed on the cover main body 16, anda terminal plate 19 laid over the cover main body 16.

The cover main body 16 is made of a conductive material, and connectedto the positive plate 24 through the connecting terminal 21. A throughhole 17 is formed in the center part of the cover main body 16.

The exhaust valve 18 is in closely contact with the top face of thecover main body 16 so as to block the through hole 17. The exhaust valve18 is formed of an elastic material such as rubber, for example, andelastically deformed by an external force.

The terminal plate 19 is a conductive plate covering the exhaust valve18.

More specifically, the terminal plate 19 presses the exhaust valve 18downward, and is connected to the cover main body 16. The terminal plate19 is provided with a discharge hole 20 to emit a gas in the batterycase 11. The discharge hole 20 emits a gas in the battery case 11 in thecase where a pressure in the battery case 11 reaches a predeterminedvalue or more. The exhaust valve 18 is elastically deformed when appliedwith a certain internal pressure or more through the through hole 17,and discharges a gas from the discharge hole 20 to the outside of thebattery 10.

An elastically deformable insulator 22 is sandwiched between the opening12A of the battery case main body 12 and the cover 15 for sealing. Theinsulator 22 insulates the battery case main body 12 from the cover 15.

As shown in FIG. 29, the electrode body 23 is a cylindrical memberaccommodated in the accommodation space S of the battery case main body12, and includes the positive plate 24, the negative plate 26, and theseparator 25 disposed between them. The electrode body 23 is wound in acoil shape around a hollow portion HO, which is a hollow space (acylindrical space) in a range of a predetermined length from the axis A(the axis of the tubular portion 13 and the electrode body 23) in thestate in which the positive plate 24, the negative plate 26, and theseparator 25 are laid on each other.

The electrode body 23 includes an inner circumferential face 23A on thehollow portion HO side and an outer circumferential face 23B on theopposite side of the inner circumferential face 23A, and the outercircumferential face 23B contacts the inner face 13A of the tubularportion 13. The positive plate 24 is disposed on the innercircumferential face 23A of the electrode body 23, and the negativeplate 26 is disposed on the outer circumferential face 23B of theelectrode body 23. The electrode body 23 is formed in such a way thatthe positive plate 24, the negative plate 26, and the separator 25 arelaid on each other and wound in a roll shape. A step is produced at awinding end portion 23D of the inner circumferential face 23A of theelectrode body 23 and at a winding end portion 23E of the outercircumferential face 23B of the electrode body 23 because of an innerdiameter difference in a thickness of one layer of the positive plate24, the negative plate 26, and the separator 25.

As shown in FIG. 27, the electrode body 23 accommodated in the batterycase main body 12 has a gap between the electrode body 23 and the cover15.

The outer diameter of the electrode body 23 is almost the same as theinner diameter B2 of the tubular portion 13 across the verticaldirection.

The length of the electrode body 23 in the vertical direction is thelength across almost the overall length of the accommodation space S inthe vertical direction. It is noted that a gap is formed between a topend 23C of the electrode body 23 and the diameter reducing portion 12Bof the battery case 11, and the lower end of the electrode body 23contacts the closing portion 14.

The positive plate 24 is a plate in which a mixture of a nickelhydroxide active material and a conductive cobalt compound is filled inhollow spaces of the positive electrode substrate made of nickel foam.It is noted that the nickel hydroxide active material is nickelhydroxide, for example, in the case of a nickel-cadmium rechargeablecell, whereas the nickel hydroxide active material is nickel hydroxideadded with calcium hydroxide, for example, in the case of a nickel-metalhydride rechargeable cell.

The negative plate 26 includes a negative current collector formed of aflat, nickel-plated bored steel sheet, for example, and a negativeactive material coated on the negative current collector. It is notedthat the negative active material is a mixture of cadmium oxide powderand metal cadmium powder, for example, in the case of a nickel-cadmiumrechargeable cell, whereas the negative active material is hydrogenstorage alloy powder mainly of AB5 type (rare earth-Ni), AB3.0-3.8 type(rare earth-Mg—Ni), or AB2 type (Laves phase), for example, in the caseof a nickel-metal hydride rechargeable cell.

The separator 25 is made of polyolefin nonwoven fabric, for example, andthe separator 25 is impregnated with an electrolyte containing primarilypotassium hydroxide or sodium hydrate. The separator 25 is not providedon the outer circumferential face 23B of the electrode body 23.

The spacer 27 is formed of an elastic body, such as rubber, having acircular cylindrical shape in a cross section of a perfect circle. Morespecifically, for example, for the spacer 27, a material including aresin that does not react with the electrolyte such an acrylic resin, apolypropylene resin, and a nylon resin can be used. Moreover, a materialthat absorbs an electrolyte for swelling can be preferably used. Thespacer 27 is accommodated in the hollow portion HO partitioned by theinner circumferential face 23A of the electrode body 23, and an outerdiameter B1 of the spacer 27 (the diameter in the lateral direction) isalmost the same as the inner diameter of the electrode body 23 (thediameter in the lateral direction). The spacer 27 is slightly largerthan the inner diameter of the electrode body 23 (the diameter in thelateral direction) in the natural state before accommodated in thehollow portion HO (before elastically deformed). Thus, the spacer 27 isformed of an elastic body and accommodated in the hollow portion HO inthe elastically contracted state, so that the inner circumferential face23A of the electrode body 23 can be pressed against almost all aroundthe tubular portion 13 side using elastic repulsion force. It is notedthat in this embodiment, as shown in FIG. 28, since the inner diameterof the electrode body 23 is not constant due to the thickness of the endportion 23D of the inner circumferential face 23A of the electrode body23, a part of the inner circumferential face 23A of the electrode body23 does not contact a circular outer circumferential face 27C of thespacer 27. Therefore, such a configuration may be possible for anotherembodiment in which the outer circumferential face shape of the spacer27 is changed in accordance with the difference in the inner diameter ofthe electrode body 23 (a projecting portion to enter the recess of theelectrode body 23 is provided on the outer circumferential face of thespacer), the outer circumferential face of the spacer 27 contacts theinner circumferential face 23A even in the portion where the innerdiameter of the outer circumferential face 27C is different, and theunsteadiness of the electrode body 23 is further suppressed.

As shown in FIG. 27, the length of the spacer 27 in the verticaldirection is the length across almost the overall length of theaccommodation space S in the vertical direction. Thus, the length of thespacer 27 in the vertical direction is almost the same length as thelength of the electrode body 23 in the vertical direction. It is notedthat the gap is formed between the top end 27A of the spacer 27 and thediameter reducing portion 12B of the battery case 11, and a lower end27B of the spacer 27 contacts the closing portion 14.

For the assembly of the battery 10, for example, the battery 10 can beformed in such a way that the electrode body 23 is wound around thespacer 27 in a coiled shape, the outer circumferential face 23B of theelectrode body 23 is pressurized using a plurality of pressure rollersto accommodate the spacer 27 and the electrode body 23 in the batterycase main body 12 while maintaining the shape of the electrode body 23,and then the cover 15 is put on.

According to this embodiment, the following operation and effect areexerted. The battery 10 according to this embodiment includes thebattery case 11 including the tubular portion 13 having theaccommodation space S in the inside, the electrode body 23 accommodatedin the accommodation space S, in which the positive plate 24, thenegative plate 26, and the separator 25 disposed between them are woundaround the hollow portion HO, the outer circumferential face 23B on theopposite side of the inner circumferential face 23A on the hollowportion HO side contacts the inner face 13A of the tubular portion 13,and the spacer 27 accommodated in the hollow portion HO and contactingthe inner circumferential face 23A of the electrode body 23.

With this configuration, the electrode body 23 is wound around thehollow portion HO, so that the amount of electrodes used can bedecreased as compared with the case where the electrode body 23 is woundwith no hollow portion HO.

Moreover, the spacer 27 is accommodated in the hollow portion HO, andcontacts the inner circumferential face 23A of the electrode body 23,and the outer circumferential face 23B of the electrode body 23 on theopposite side of the inner circumferential face 23A on the hollowportion HO side contacts the inner face 13A of the tubular portion 13,so that the electrode body 23 can be supported using the spacer 27 fromthe inner side, and can be supported using the tubular portion 13 fromthe outer side. Therefore, the unsteadiness of the electrode body 23 inthe battery case 11 can be suppressed.

Accordingly, the amount of electrodes used can be decreased whilesuppressing the unsteadiness of the electrode body 23 in the batterycase 11.

Furthermore, the spacer 27 presses the electrode body 23 to the tubularportion 13 side.

With this configuration, force that the spacer 27 supports the electrodebody 23 in the tubular portion 13 can be improved.

In addition, the spacer 27 is formed of an elastic body.

With this configuration, it is possible that the electrode body 23 ispressed to the inner face 13A of the tubular portion 13 side using theelastic force of the spacer 27 to position the electrode body 23.

Moreover, the spacer 27 contacts all around the inner circumferentialface 23A of the electrode body 23.

With this configuration, the unsteadiness of the electrode body 23 inthe battery case 11 can be further suppressed.

Furthermore, the battery case 11 is of conductivity, the negative plate26 is disposed on at least a part of the outer face of the electrodebody 23, and the negative plate 26 of the outer face contacts the innerface 13A of the tubular portion 13.

With this configuration, the negative plate 26 of the electrode body 23can be electrically connected to the battery case 11.

Second Embodiment

Next, a second embodiment in the fourth aspect of the present inventionwill be described with reference to FIG. 30.

A battery 28 according to this embodiment uses a spacer 29 formed in acylindrical shape in which a lightening hole 29A is penetrated throughthe cylindrical spacer 27 according to the first embodiment. The otherconfigurations are the same as the first embodiment, the sameconfigurations as those of the first embodiment are designated by thesame reference numerals and signs, and the description is omitted.

A battery case 11 and an electrode body 23 are the same as those in thefirst embodiment.

The spacer 29 is formed with the circular lightening hole 29Apenetrating in the vertical direction. It is noted that the length ofthe spacer 29 in the vertical direction and the outer diameter and thematerial of the spacer 29 can be made the same as those in the firstembodiment.

It is noted that an electrolyte leaking out of a separator 25 can bestored in a space in the lightening hole 29A.

According to this embodiment as described above, the lightening hole 29Ais formed in the spacer 29, so that materials for used in the spacer 29can be decreased.

Third Embodiment

Next, a third embodiment in the fourth aspect of the present inventionwill be described with reference to FIG. 31. A battery 30 according tothis embodiment uses a rectangular tubular spacer 31. The rectangulartubular spacer 31 partially contacts an inner circumferential face 23Aof an electrode body 23. The other configurations are the same as thefirst embodiment, the same configurations as those of the firstembodiment are designated by the same reference numerals and signs, andthe description is omitted.

A battery case 11 and an electrode body 23 are the same as those in theembodiments above.

The spacer 31 is in a rectangular tube in which a rectangular lighteninghole 32 penetrates in the vertical direction, and the cross section isthe same shape across the vertical direction. The length and thematerial of the spacer 31 in the vertical direction can be made the sameas those in the first embodiment. Four corners 31A to 31D of the spacer31 contact different locations on the inner circumferential face 23A ofthe electrode body 23. It is noted that all the corners 31A to 31D ofthe spacer 31 may not contact the inner circumferential face 23A of theelectrode body 23. For example, such a configuration may be possible inwhich one corner or a plurality of the corners of the spacer 31 contactsthe inner circumferential face 23A of the electrode body 23 and anothercorner or a plurality of the other corners does not contact the innercircumferential face 23A of the electrode body 23. Moreover, the spacer31 is not limited to a rectangular tube. The spacer 31 may be arectangular tube in other polygons (such as a triangle and a pentagon).Furthermore, the spacer 31 is not limited to one formed with thelightening hole 32. The spacer 31 may have a square shape in which theinside of the spacer is filled.

Fourth Embodiment

Next, a fourth embodiment in the fourth aspect of the present inventionwill be described with reference to FIG. 32. In a battery 33 accordingto this embodiment, a spacer 34 is formed in a cross shape. The otherconfigurations are the same as the first embodiment, the sameconfigurations as those of the first embodiment are designated by thesame reference numerals and signs, and the description is omitted.

A battery case 11 and an electrode body 23 are the same as those in theembodiments above.

The length of the spacer 34 in the vertical direction and the outerdiameter and the material of the spacer 34 can be made the same as thosein the first embodiment. The spacer 34 has a cross shape in which thecross section is the same across the vertical direction. Fourplate-shaped projecting portions 34A to 34D are disposed at equal angles(an angle of 90 degrees) as an axis A of a tubular portion 13 is in thecenter.

Tip end portions 35A to 35D of the plate-shaped projecting portions 34Ato 34D contact an inner circumferential face 23A of the electrode body23. The plate-shaped projecting portions 34A to 34D may have the sameprojecting dimensions. However, such a configuration may be possible inwhich the projecting dimensions of the plate-shaped projecting portions34A to 34D are varied in accordance with the inner diameter differencecaused by an end portion 23D of the inner circumferential face 23A ofthe electrode body 23, and a gap between the spacer 34 and the innercircumferential face 23A of the electrode body 23 is eliminated tofurther suppress the unsteadiness of the electrode body 23.

It is noted that an electrolyte leaking out of the separator 25 can bestored in a space between the spacer 34 and the electrode body 23.

Other Embodiments

The present invention is not limited to the embodiments described withreference to the drawing. For example, the following embodiments will beincluded in the technical scope of the present invention.

(1) The materials of the spacers 27, 29, 31, and 34 are not limited tothe materials in the embodiments, and various materials can be used. Forexample, a metal such as stainless steel or a conductive resin can alsobe used, not limited to an insulating material.

(2) The shapes of the spacers 27, 29, 31, and 34 are not limited to theshapes in the embodiments, and the shapes may be a shape based on theshape of the inner circumferential face of the electrode body 23. Forexample, in the case where the inner circumferential face of theelectrode body is in an ellipse or an oval, the outer circumferentialface of the spacer may be formed in an ellipse or an oval. In this case,the spacer may be a spacer having a space in the inside filled, or maybe a tubular spacer.

(3) In the embodiment above, the negative plate 26 is disposed onthroughout the outer face of the electrode body 23. However, the presentinvention is not limited thereto. For example, such a configuration maybe possible in which the negative plate 26 is disposed on a part of theouter face of the electrode body 23 and the negative plate 26 of theouter face contacts the inner face 13A of the tubular portion 13.

(4) The spacer may be formed of an elastic body other than rubber. Forexample, the spacer may be made of a spring. More specifically, forexample, such a configuration may be possible in which a plate spring iswound to press the inner circumferential face 23A of the electrode body23 using elastic force.

(5) The spacer is not limited to an elastic body, and may use a plasticbody (an inelastic body). In this case, for example, the outer diameterB1 of the spacer (the diameter in the lateral direction) is almost thesame as the inner diameter of the electrode body 23 (the diameter in thelateral direction), or slightly larger than the inner diameter of theelectrode body 23. Also with this configuration, the outercircumferential face 27C of the spacer 27 contacts the innercircumferential face 23A of the electrode body 23, or presses the innercircumferential face 23A of the electrode body 23 in the state in whichthe spacer 27 is accommodated in the hollow portion HO.

Fifth Aspect First Embodiment

A first embodiment in a fifth aspect of the present invention will bedescribed below with reference to FIGS. 33 to 36.

A battery 10 according to this embodiment is an alkaline secondarybattery such as a nickel-metal hydride rechargeable cell. For example,the battery 10 is a low capacity type such as an AA battery (“R6” in theIEC (International Electrotechnical Commission), and “AA” in the UnitedStates) having a capacity of 1800 mAh or less and an AAA battery (“R03”in the IEC, and “AAA” in the United States) having a capacity of 650 mAhor less. In the following, the vertical direction and in the lateraldirection will be described with reference to the directions in FIG. 34.

As shown in FIG. 33, the battery 10 is configured by a metal batterycase 11, an electrode body 23 having a cylindrical shape (an example of“a cylindrical electrode body”), and a conductive spacer 27 disposedbetween the electrode body 23 and the battery case 11. The battery case11 is defined in the size according to the specification. The batterycase 11 has a shape elongated in the vertical direction, has anaccommodation space S in the inside, and has a nickel-plated surface.The battery case 11 includes a cylindrical battery case main body 12with a bottom having an opening 12A opened at one end side and the otherend closed, and a cover 15 that closes the opening 12A of the batterycase main body 12.

The battery case main body 12 becomes a negative electrode terminal ofthe battery 10 by contacting the negative plate 26, described later, andincludes a tubular portion 13 and a closing portion 14 that closes thelower end of the tubular portion 13.

The tubular portion 13 has a cylindrical shape, and the innercircumferential face thereof has a perfect circle in which the diameterfrom a center axis A of the tubular portion 13 is constant in FIG. 34.The inside of the tubular portion 13 is the accommodation space S inwhich an electrode body 23, described later, can be accommodated, andthe tubular portion 13 has an inner diameter B2 (the inner diameter inthe lateral direction in FIG. 34) larger than an outer diameter B1 ofthe electrode body 23 (the outer diameter in the lateral direction inFIG. 34).

The closing portion 14 is formed of a circular plate member, andintegrally formed with the tubular portion 13.

The cover 15 is connected to a positive plate 24, described later,through an elastic connecting terminal 21, and becomes a positiveelectrode terminal of the battery 10. The cover 15 includes a flat covermain body 16, an elastic body 18 placed on the cover main body 16, and aterminal plate 19 laid on the cover main body 16.

The cover main body 16 is made of a conductive martial, for example, andconnected to the positive plate 24 through the connecting terminal 21. Athrough hole 17 is formed in the center part of the cover main body 16.

The elastic body 18 is in closely contact with the top face of the covermain body 16 so as to block the through hole 17. The elastic body 18 ismade of a material such as rubber, for example, and elastically deformedby an external force.

The terminal plate 19 is a conductive plate covering the elastic body18.

More specifically, the terminal plate 19 presses the elastic body 18downward, and is connected to the cover main body 16. The terminal plate19 is provided with a discharge hole 20 to emit a gas in the batterycase 11. The discharge hole 20 emits a gas in the battery case 11 in thecase where a pressure in the battery case 11 reaches a predeterminedvalue or more. The elastic body 18 is elastically deformed when appliedwith a certain internal pressure or more through the through hole 17,and discharges a gas from the discharge hole 20 to the outside of thebattery 10.

An elastically deformable insulator 22 is sandwiched between the opening12A of the battery case main body 12 and the cover 15 for sealing. Theinsulator 22 insulates the battery case main body 12 from the cover 15.

The electrode body 23 is accommodated in the accommodation space S inthe battery case 11, and disposed in the battery case main body 12 as agap is provided between the electrode body 23 and the cover 15, in whichthe positive plate 24, the negative plate 26, and a separator 25disposed between them and having an electrolyte are laid on each other,and they are wound clockwise in a coiled shape, for example, along theinner face of the tubular portion 13.

The positive plate 24 is a plate in which a mixture of a nickelhydroxide active material and a conductive cobalt compound is filled inhollow spaces of the positive electrode substrate made of nickel foam.It is noted that the nickel hydroxide active material is nickelhydroxide, for example, in the case of a nickel-cadmium rechargeablecell, whereas the nickel hydroxide active material is nickel hydroxideadded with calcium hydroxide, for example, in the case of a nickel-metalhydride rechargeable cell.

The negative plate 26 includes a negative current collector formed of aflat, nickel-plated bored steel sheet, for example, and a negativeactive material coated on the negative current collector. It is notedthat the negative active material is a mixture of cadmium oxide powderand metal cadmium powder, for example, in the case of a nickel-cadmiumrechargeable cell, whereas the negative active material is hydrogenstorage alloy powder mainly of AB5 type (rare earth-Ni), AB3.0-3.8 type(rare earth-Mg—Ni), or AB2 type (Laves phase), for example, in the caseof a nickel-metal hydride rechargeable cell.

The separator 25 is made of polyolefin nonwoven fabric, for example, andthe separator 25 is impregnated with an electrolyte containing primarilypotassium hydroxide or sodium hydrate.

The separator 25 is not disposed on the outer circumferential portion ofthe electrode body 23, and the negative plate 26 is disposed on theouter circumferential portion of the electrode body 23 (the faceopposite to the inner face of the tubular portion 13).

The electrode body 23 is formed in such a way that the positive plate24, the negative plate 26, and the separator 25 are laid on each otherand wound in a roll shape. As shown in FIG. 34, the outercircumferential portion of the electrode body 23 is a diameter reducingportion 23A in which the outer diameter B1 of a line segment passingthrough the center axis of the electrode body 23 (the same as the centeraxis A of the tubular portion 13) is smaller than the inner diameter B2of the tubular portion 13. In this embodiment, since the outer diameterB1 of the electrode body 23 is smaller than the inner diameter B2 of thetubular portion 13 across the vertical direction, the outercircumferential portion of the electrode body 23 is entirely thediameter reducing portion 23A.

It is noted that the center part of the electrode body 23 has a hole 23Cinto which a shaft (not shown) is inserted when winding the positiveplate 24, the negative plate 26, and the separator 25. However, theshaft may be left, not pulled out.

The spacer 27 is a conductive member disposed between an outer face 23Bof the electrode body 23 and an inner face 13A of the tubular portion 13to fix the position in the radial direction with respect to the tubularportion 13 of the electrode body 23. As shown in FIG. 36, the spacer 27has a ring shape.

More specifically, for the shape of the spacer 27, the spacer 27includes an inner cylinder portion 28 having almost the same innerdiameter as the outer diameter B1 of the electrode body 23 and intowhich the electrode body 23 is inserted with almost no gap, an outercylinder portion 29 having almost the same outer diameter as the innerdiameter B2 of the tubular portion 13 of the battery case 11 andinserted into the tubular portion 13 with almost no gap, and aplate-shaped coupling portion 30 that joins the inner cylinder portion28 to the outer cylinder portion 29, in which the inner cylinder portion28, the outer cylinder portion 29, and the coupling portion 30 areintegrally formed with each other. The coupling portion 30 is formed atpredetermined distance (a predetermined angle) in the circumferentialdirection of the inner cylinder portion 28.

A space is formed in the portion where the coupling portion 30 is notprovided between the inner cylinder portion 28 and the outer cylinderportion 29 in the spacer 27. The shape of the spacer is not limited tothe configuration. For example, a spacer having a filled portion betweenthe inner cylinder portion 28 and the outer cylinder portion 29 may beused. In the case where the inside is filled, the portion is filled witha material the same as the material of the spacer 27, or may be filledwith a different material.

For the material of the spacer 27, various conductive metals such asstainless steel can be used, for example. However, preferably, amaterial that does not react with an electrolyte is used. Moreover, aconductive material may be used other than a metal. For example, aconductive resin (such as conductive rubber) may be used.

It is noted that in the accommodation space S in the battery case 11,the space other than the space in which the electrode body 23 and thespacer 27 are disposed is an electrolyte storage space 33 in which anelectrolyte leaking out of the separator 25 is stored.

It is noted that for the assembly of the battery 10, the battery 10 canbe formed in such a way that the wound electrode body 23 is insertedinto the battery case main body 12 in the state in which the woundelectrode body 23 is inserted into the inner cylinder portion 28 of thespacer 27 and the cover 15 is then put on (FIG. 36).

According to this embodiment, the following operation and effect areexerted.

The battery 10 includes the conductive battery case 11, the electrodebody 23 including the positive plate 24, the negative plate 26, and theseparator 25 disposed between the positive plate 24 and the negativeplate 26 and including the diameter reducing portion 23A whose outerdiameter B1 is smaller than the inner diameter 13A of the battery case11, and the conductive spacer 27 disposed between the outercircumferential face of the diameter reducing portion 23A and the innerface of the battery case 11 to electrically connect the electrode body23 to the battery case 11.

With this configuration, the amount of electrodes used can be decreasedas compared with the case where the electrode body 23 does not includethe diameter reducing portion 23A whose outer diameter B1 is smallerthan the inner diameter B2 of the battery case 11. Moreover, the spacer27 is disposed between the outer circumferential face of the diameterreducing portion 23A and the inner face of the battery case 11, so thatthe unsteadiness of the electrode body 23 in the battery case 11 can besuppressed.

Accordingly, the amount of electrodes used can be decreased whilesuppressing the unsteadiness of the electrode body 23 in the batterycase 11.

Furthermore, the conductive spacer 27 electrically connects theelectrode body 23 to the battery case 11, so that the spacer 27 forpreventing the unsteadiness of the electrode body 23 can be used forelectrical connection between the electrode body 23 and the battery case11.

In addition, the battery case 11 includes the tubular portion 13 inwhich the electrode body 23 and the spacer 27 are accommodated. Theelectrode body 23 includes the positive plate 24, the negative plate 26,and the separator 25 laid on each other in the radial direction of thetubular portion 13 (in an intersecting direction) with respect to thevertical direction (one direction). The spacer 27 is accommodatedbetween the outer face of the electrode body 23 and the inner face ofthe tubular portion 13 in the intersecting direction.

The electrode body 23 wound in a cylindrical shape has problems in thatit is necessary to change the width at which the electrode is cut and itis necessary to change the manufacturing process steps or devices whenthe length of the tubular portion 13 in the axial direction in theelectrode body 23 is decreased in order to reduce the materials of theelectrode body 23. According to this embodiment, it is not necessary tochange the length of the tubular portion 13 in the axial direction inthe electrode body 23, so that manufacturing costs can be decreased.

The spacer 27 is disposed in the middle portion of the electrode body 23in the axial direction.

With this configuration, it is possible to prevent the deformation ofthe middle portion of the electrode body 23 in the axial direction, andthe middle portion is relatively prone to be deformed.

The negative plate 26 is disposed at least on the outer face of theelectrode body 23, and the negative plate 26 on the outer face of theelectrode body 23 contacts the spacer 27.

With this configuration, for example, the configuration can besimplified as compared with a configuration in which the negative plate26 is electrically connected to the spacer 27 using a lead wire.

The spacer 27 surrounds all the outer circumferential portion of thediameter reducing portion 23A. Thus, it is possible to suppress thedeformation of the electrode body 23 caused by locally and externallyapplying force from the spacer 27 to the electrode body 23, and it ispossible to increase the contact area between the electrode body 23 andthe spacer 27, so that it is possible to decrease electrical resistancebetween the negative plate 26 and the battery case 11.

The electrolyte storage space 33 is provided between the outer face 23Bof the electrode body 23 and the inner face 13A of the battery case 11.

With this configuration, even though the separator 25 is excessivelyimpregnated with an electrolyte in order to prolong a battery life andthe electrolyte leaks out the electrode body 23, the electrolyte can bestored in the electrolyte storage space 33. Moreover, the internalpressure increase in the battery 10 can be relaxed because of theprovision of the electrolyte storage space 33, and a battery 10 of highenergy density and a long life can be provided.

Furthermore, when the battery 10 is tilted and the electrolyte includedin the separator 25 is decreased, the leaked electrolyte stored in theelectrolyte storage space 33 is again absorbed in the separator 25 dueto a capillary action or the like, so that an internal resistanceincrease in the battery 10 caused by liquid leakage of the separator 25can be prevented, and the battery 10 of a longer life can be provided.

Second Embodiment

Next, a second embodiment in the fifth aspect of the present inventionwill be described with reference to FIG. 37.

In this embodiment, as shown in FIG. 37, a spacer 31 in a mesh form isused. The other configurations are the same as the first embodiment, thesame configurations as those of the first embodiment are designated bythe same reference numerals and signs, and the description is omitted.

Braided wires 31A are used for the spacer 31, in which metal small-gagewires are braided in a mesh form, for example, and are formed using ametal such as aluminum and an aluminum alloy. It is noted that othermetals and conductive members other than metals may be used for thespacer.

The spacer 31 is formed in a ring shape as a whole by winding thebraided wires 31A for a plurality of times. The inner circumferentialportion contacts an outer circumferential portion 23B of an electrodebody 23, and the outer circumferential portion contacts an innercircumferential portion 13A of a tubular portion 13.

Moreover, the spacer 31 is not limited to the spacer formed of thebraided wires 31A entirely. For example, such a configuration may bepossible in which the braided wires 31A cover a frame for supporting theshape of the braided wires 31A (a conductive member). For the frame, forexample, the frame may be formed of a material of low conductivity (highelectrical resistance), or may be formed of a resin that does not reactwith an electrolyte such as an acrylic resin, a polypropylene resin, anda nylon resin, or a material such as stainless steel.

According to this embodiment as described above, the flexibility of thebraided wires 31A braided in a mesh form can deform the shape of thespacer 31, so that accommodation into the battery case 11 can befacilitated. Furthermore, the unsteadiness of the spacer 31 in thebattery case 11 can be suppressed because of the flexibility of thebraided wires 31A.

Third Embodiment

Next, a third embodiment in the fifth aspect of the present inventionwill be described with reference to FIG. 38.

This embodiment is different from the spacer 27 according to the firstembodiment in that a spacer 32 in a coil form is used. The sameconfigurations as those of the first embodiment are designated by thesame reference numerals and signs, and the description is omitted.

The spacer 32 is formed in which a wire material 34 formed of a metalline such as a bare copper wire or a conductive wire other than a metalis wound in a spiral shape or in a coiled shape.

For the thickness and the wire turns of the wire material, such athickness and wire turns are set that a space between an outer diameter23B of an electrode body 23 and an inner face 13A of a battery case 11can be filled.

According to this embodiment, the spacer 32 can be formed by winding thewire material 34, so that manufacturing costs can be decreased ascompared with the case where a mold or the like is used to shape theshape of the spacer.

Other Embodiments

The present invention is not limited to the embodiments described withreference to the drawing. For example, the following embodiments will beincluded in the technical scope of the present invention.

(1) In the embodiment above, since the outer diameter of the electrodebody 23 is constant, the diameter reducing portion 23A is formed acrossthe length of the electrode body 23. However, such a configuration maybe possible in which the outer diameter of the electrode body 23 ischanged in accordance with the position in the axial direction to formthe diameter reducing portion on a part of the electrode body 23. Forexample, such a configuration may be possible in which the electrodebody is provided with a diameter increasing portion having almost thesame outer diameter as the inner diameter of the tubular portion 13 anda diameter reducing portion whose outer diameter is smaller than thediameter increasing portion.

(2) In the embodiment above, the spacers 27, 31, and 32 are mounted onthe middle portion between the tubular portion 13 and the electrode body23 in the vertical direction. However, such a configuration may bepossible in which the spacer is mounted at a portion other than themiddle portion between the tubular portion 13 and the electrode body 23in the vertical direction.

(3) The shape and the material of the spacer are not limited to theshape and the material in the embodiments. For example, an annularelastic material formed of an elastically deformable plate member or awire material in a coiled shape or in a spiral shape may be used for thespacer. For example, as shown in FIG. 39, such a configuration may bepossible in which a wire material 35 made of an elastically deformablemetal in a spiral shape is used for a spacer 36 in a coil spring formprovided across the vertical direction of the electrode body 23. Thespacer 36 has a smaller diameter from the center axis at an upper endportion 36A and a lower end portion 36B, and the diameter from thecenter axis is increased as closer to the middle portion in the verticaldirection. The middle portion of the largest diameter elasticallycontacts the inner face 13A of the tubular portion 13, and the upper endportion 36A and the lower end portion 36B of the smallest diameterelastically contact an outer face 23B of the electrode body 23.Moreover, the spacer is not limited to a coil spring. The spacer may beformed of a wound metal plate spring. More specifically, as shown inFIG. 40, for example, such a configuration may be possible in which aspacer 37 formed of a wound metal plate spring is mounted between theelectrode body 23 and the tubular portion 13 in the elastic deformationstate, and the spacer 37 spring-biases the inner face 13A of the tubularportion 13 and the outer face 23B of the electrode body 23 using elasticrepulsion force to electrically connect the electrode body 23 to thetubular portion 13.

(4) The inner face 13A of the tubular portion 13 may not contact allaround the spacer. For example, such a configuration may be possible inwhich a portion surrounding the electrode body 23 is provided on theelectrode body 23 side of the spacer and a portion partially contactingthe inner face of the electrode body 23 is provided on the inner faceside of the tubular portion 13, not surrounding the electrode body 23.

(5) The negative plate 26 is entirely disposed on the outercircumferential portion of the electrode body 23. However, the negativeplate 26 may be disposed on a part of the outer circumferential portionof the electrode body 23. Moreover, the negative plate 26 may not bedisposed on the outer circumferential portion of the electrode body 23.In this case, the negative plate 26 may be electrically connected to thespacer using a lead wire or the like.

Sixth Aspect First Embodiment

A first embodiment in a sixth aspect of the present invention will bedescribed with reference to FIGS. 41 to 44.

A battery 10 according to this embodiment is an alkaline secondarybattery such as a nickel-metal hydride rechargeable cell. For example,the battery 10 is a low capacity type such as an AA battery (“R6” in theIEC (International Electrotechnical Commission), and “AA” in the UnitedStates) having a capacity of 1800 mAh or less and an AAA battery (“R03”in the IEC, and “AAA” in the United States) having a capacity of 650 mAhor less.

In the following, a description will be given for the vertical directionand in the lateral direction with reference to the directions shown inFIG. 42.

As shown in FIG. 41, the battery 10 includes a metal battery case 11, anelectrode body 23 having a cylindrical shape accommodated in the batterycase 11 (an example of “a cylindrical electrode body”), and a spacer 27contiguous to the electrode body 23 in the battery case 11. The batterycase 11 is defined in the size according to the specification. Thebattery case 11 has a shape elongated in the vertical direction, has anaccommodation space S in the inside, and has a nickel-plated surface.The battery case 11 includes a cylindrical battery case main body 12with a bottom having an opening 12A opened at one end side and the otherend closed, and a cover 15 that closes the opening 12A of the batterycase main body 12.

The battery case main body 12 becomes a negative electrode terminal ofthe battery 10 by contacting the negative plate 26, described later, andincludes a tubular portion 13 and a closing portion 14 that closes thelower end of the tubular portion 13.

The tubular portion 13 has a cylindrical shape. As shown in FIG. 42, theinner circumferential portion and the outer circumferential portion ofthe tubular portion 13 have a perfect circle in which the diameter froman axis A2 passing through the center of the circle of the tubularportion 13 is constant. The inside of the tubular portion 13 is theaccommodation space S in which an electrode body 23, described later,can be accommodated, and the tubular portion 13 has an inner diameter B2(the diameter of the tubular portion 13 in the lateral direction) largerthan an outer diameter B1 of the electrode body 23 (the diameter of theelectrode body 23 in the lateral direction).

To the upper end portion of the tubular portion 13, a diameter reducingportion 12B is connected. The diameter reducing portion 12B projects onthe inner side of the tubular portion 13 to reduce the inner diameter.The diameter reducing portion 12B partitions the top end of theaccommodation space S. On the diameter reducing portion 12B, a fittingportion 12C is formed into which the peripheral portion of the cover 15is fit.

The closing portion 14 is formed of a circular plate member, andintegrally formed with the tubular portion 13.

The cover 15 is connected to a positive plate 24, described later,through an elastic connecting terminal 21, and becomes a positiveelectrode terminal of the battery 10. The cover 15 includes a flat covermain body 16, an elastic body 18 placed on the cover main body 16, and aterminal plate 19 laid over the cover main body 16.

The cover main body 16 is made of a conductive material, and connectedto the positive plate 24 through the connecting terminal 21. A throughhole 17 is formed in the center part of the cover main body 16.

The elastic body 18 is in closely contact with the top face of the covermain body 16 so as to block the through hole 17. The elastic body 18 ismade of a material such as rubber, for example, and elastically deformedby an external force.

The terminal plate 19 is a conductive plate covering the elastic body18.

More specifically, the terminal plate 19 presses the elastic body 18downward, and is connected to the cover main body 16. The terminal plate19 is provided with a discharge hole 20 to emit a gas in the batterycase 11. The discharge hole 20 emits a gas in the battery case 11 in thecase where a pressure in the battery case 11 reaches a predeterminedvalue or more. The elastic body 18 is elastically deformed when appliedwith a certain internal pressure or more through the through hole 17,and discharges a gas from the discharge hole 20 to the outside of thebattery 10.

An elastically deformable insulator 22 is sandwiched between the opening12A of the battery case main body 12 and the cover 15 for sealing. Theinsulator 22 insulates the battery case main body 12 from the cover 15.

The electrode body 23 is accommodated in the accommodation space S inthe battery case 11, and disposed in the battery case main body 12 as agap is provided between the electrode body 23 and the cover 15.

The electrode body 23 is formed in such a way that the positive plate24, the negative plate 26, and a separator 25 that is disposed betweenthem and has an electrolyte are laid on each other, and are woundclockwise in a coiled shape, for example, along the inner face 13A ofthe tubular portion 13. The length of the electrode body 23 in thevertical direction is the length across almost the overall length of theaccommodation space S in the vertical direction. It is noted that a gapis formed between a top end 23C of the electrode body 23 and thediameter reducing portion 12B of the battery case 11, and the lower endof the electrode body 23 contacts the closing portion 14.

The positive plate 24 is a plate in which a mixture of a nickelhydroxide active material and a conductive cobalt compound is filled inhollow spaces of the positive electrode substrate made of nickel foam.It is noted that the nickel hydroxide active material is nickelhydroxide, for example, in the case of a nickel-cadmium rechargeablecell, whereas the nickel hydroxide active material is nickel hydroxideadded with calcium hydroxide, for example, in the case of a nickel-metalhydride rechargeable cell.

The negative plate 26 includes a negative current collector formed of aflat, nickel-plated bored steel sheet, for example, and a negativeactive material coated on the negative current collector. It is notedthat the negative active material is a mixture of cadmium oxide powderand metal cadmium powder, for example, in the case of a nickel-cadmiumrechargeable cell, whereas the negative active material is hydrogenstorage alloy powder mainly of AB5 type (rare earth-Ni), AB3.0-3.8 type(rare earth-Mg—Ni), or AB2 type (Laves phase), for example, in the caseof a nickel-metal hydride rechargeable cell.

The separator 25 is made of polyolefin nonwoven fabric, for example, andthe separator 25 is impregnated with an electrolyte containing primarilypotassium hydroxide or sodium hydrate.

The separator 25 is not disposed on the outer circumferential face 23Bof the electrode body 23, and the negative plate 26 is disposed on theouter circumferential face 23B of the electrode body 23.

The electrode body 23 is formed in such a way that the positive plate24, the negative plate 26, and the separator 25 are laid on each otherand wound in a roll shape. As shown in FIG. 42, the electrode body 23has a diameter reducing portion 23A that the outer diameter B1 of theelectrode body 23 is smaller than the inner diameter B2 of the tubularportion 13. In this embodiment, since the outer diameter B1 of theelectrode body 23 is smaller than the inner diameter B2 of the tubularportion 13 across the vertical direction, the overall length of theouter circumferential face 23B of the electrode body 23 in the verticaldirection is the diameter reducing portion 23A.

The spacer 27 is a member disposed between the outer circumferentialface 23B of the electrode body 23 and the inner face 13A of the tubularportion 13 of the battery case 11 to fix the position in theintersecting direction with respect to an axis A1 of the electrode body23 in the tubular portion 13. As shown in FIG. 44, the spacer 27 is in asquare tube.

More specifically, the spacer 27 is formed in which walls 28A to 28Dmade of four flat plates are formed in a ring shape in the verticaldirection. As shown in FIG. 42, the length of the spacer 27 in thevertical direction is the length across almost the overall length of theaccommodation space S in the vertical direction. Thus, the length of thespacer 27 in the vertical direction is almost the same length as thelength of the electrode body 23 in the vertical direction. It is notedthat a gap is formed between the top end 27A of the spacer 27 and thediameter reducing portion 12B of the battery case 11.

The lower end of the spacer 27 contacts the closing portion 14.

As shown in FIG. 43, in the spacer 27, one wall 28A opposite to theelectrode body 23 contacts the outer face 23B of the electrode body 23.Corners 28E and 28F of the wall 28C on the opposite side of the wall 28Acontact the inner face 13A of the tubular portion 13.

The spacer 27 is made of a resin that does not react with theelectrolyte such as an acrylic resin, a polypropylene resin, and a nylonresin or a material such as stainless steel, for example.

It is noted that in the accommodation space S in the battery case 11, anelectrolyte leaking out of the separator 25 can be stored in the spaceother than in a portion on which the electrode body 23 and the walls 28Ato 28D are disposed.

According to this embodiment, the following operation and effect areexerted.

The battery 10 according to this embodiment includes the battery case 11including the tubular portion 13 having the accommodation space S in theinside, and the electrode body 23 accommodated in the accommodationspace S, including the positive plate 24, the negative plate 26, and theseparator 25 disposed between them that are laid on each other in theintersecting direction of the axis A2 of the tubular portion 13, andhaving the diameter reducing portion 23A whose outer diameter B1 issmaller than the inner diameter B2 of the tubular portion 13, and thespacer 27 disposed between the tubular portion 13 and the electrode body23 and contacting the inner face 13A of the tubular portion 13 and theouter face 23B of the electrode body 23. The electrode body 23 in thetubular portion 13 is disposed at a position at which the axis A1 of theelectrode body 23 is different from the axis A2 of the tubular portion13.

According to this embodiment, the outer diameter B1 of the electrodebody 23 is smaller than the inner diameter B2 of the battery case 11, sothat the amount of electrodes used can be decreased as compared with thecase of using an electrode body having the outer diameter the same asthe inner diameter B2 of the battery case 11, for example. Moreover, thespacer 27 contacts the outer face 23B of the electrode body 23 and theinner face 13A of the battery case 11, so that the unsteadiness of theelectrode body 23 in the battery case 11 can be suppressed.

Accordingly, the amount of electrodes used can be decreased whilesuppressing the unsteadiness of the electrode body 23 in the batterycase 11.

Furthermore, the electrode body 23 in the tubular portion 13 is disposedat a position at which the axis A1 of the electrode body 23 is differentfrom the axis A2 of the tubular portion 13, so that the spacer 27 can bedisposed close to the axis A2 of the tubular portion 13 in the batterycase 11, and the degree of freedom of the disposition of the spacer 27can be improved. In addition, the electrode body 23 wound in acylindrical shape has problems in that it is necessary to change thewidth at which the electrode is cut and it is necessary to change themanufacturing process steps or devices when the length of the electrodebody 23 in the direction of the axis A1 is decreased in order todecrease the materials of the electrode body 23. According to thisembodiment, it is not necessary to change the length in the direction ofthe axis A1 of the tubular portion 13 of the electrode body 23, so thatmanufacturing costs can be decreased.

Moreover, the outer face 23B (the opposing face) of the electrode body23 opposite to the inner face 13A of the tubular portion 13 contacts theinner face 13A of the tubular portion 13.

With this configuration, at least one side of the electrode body 23 canbe supported by the tubular portion 13, so that the unsteadiness of theelectrode body 23 in the battery case 11 can be suppressed.

Furthermore, the battery case 11 is of conductivity, the negative plate26 is disposed at least on a part of the outer face 23B of the electrodebody 23, and the negative plate 26 of the outer face contacts the innerface 13A of the tubular portion 13.

With this configuration, the negative plate 26 of the electrode body 23can be electrically connected to the battery case 11 used as thenegative electrode terminal.

In addition, the length of the electrode body 23 in the direction of theaxis A1 is the overall length of the accommodation space S in thedirection along the direction of the axis A1, and the spacer 27 has thelength across the overall length in the direction of the axis A1 of theelectrode body 23.

With this configuration, the unsteadiness of the electrode body 23 inthe battery case 11 can be more reliably prevented.

Second Embodiment

Next, a second embodiment in the sixth aspect of the present inventionwill be described with reference to FIG. 45.

In the battery 10 according to the first embodiment, the spacer 27 is ina rectangular tube. However, as shown in FIG. 45, in a battery 31according to this embodiment, a spacer 29 has a cylindrical shape. Theother configurations are the same as the first embodiment, the sameconfigurations as those of the first embodiment are designated by thesame reference numerals and signs, and the description is omitted.

The spacer 29 has a cylindrical shape in which the inner circumferentialportion and the outer circumferential portion have a perfect circularshape. The spacer 29 is disposed between an outer face 23B of anelectrode body 23 and an inner face 13A of a tubular portion 13 to fixthe position of the electrode body 23 in the intersecting direction ofan axis A1 of the electrode body 23 in the tubular portion 13.

As similar to the first embodiment, the length of the spacer 29 in thevertical direction is the length across almost the overall length of theaccommodation space S in the vertical direction. A gap is formed betweenthe top end of the spacer 29 and a diameter reducing portion 12 of abattery case 11. The lower end of the spacer 29 contacts the closingportion 14.

The outer circumferential face of the spacer 29 includes a firstcontacting portion 30A that contacts the outer circumferential face 23Bof the electrode body 23 in a line, and a second contacting portion 30Bthat contacts the inner face 13A of the tubular portion 13 at asymmetrical position to the first contacting portion 30A with respect toa center axis C1 of the spacer 29. The material of the spacer 29 issimilar to the maternal in the first embodiment.

Other Embodiments

The present invention is not limited to the embodiments described withreference to the drawing. For example, the following embodiments will beincluded in the technical scope of the present invention.

(1) The materials of the spacer are not limited to the materials in theembodiments, and various materials can be used. For example, a metalsuch as stainless steel or a conductive resin can also be used.

(2) In the embodiments above, the outer face 23B of the electrode body23 contacts the inner face 13A of the tubular portion 13. However, theouter face 23B of the electrode body 13 may not contact the inner face13A of the tubular portion 13. At least the axis A1 of the electrodebody 23 may be disposed at a position different from the axis A2 of thetubular portion 13. In this case, it is also possible to increase thenumber of the spacers for positioning the electrode body 23 in thetubular portion 13. For example, such a configuration may be possible inwhich a plurality of spacers is provided between the outer face 23B ofthe electrode body 23 and the inner face 13A of the tubular portion 13and the electrode body 23 is positioned in the tubular portion 13 in theintersecting direction of the axis A2 using the spacers from a pluralityof directions.

Moreover, in this case, for example, when the spacer is of conductivity,the electrode body 23 can be electrically connected to the tubularportion 13 through the spacers even though the electrode body 23 doesnot contact the tubular portion 13.

(3) In the embodiments above, since the outer diameter of the electrodebody 23 is constant, the diameter reducing portion 23A whose the outerdiameter is smaller than the inner diameter B2 of the tubular portion 13is formed across the length of the electrode body 23. However, such aconfiguration may be possible in which the outer diameter of theelectrode body 23 is changed in accordance with the position in theaxial direction to form the diameter reducing portion on a part of theaxial direction of the electrode body 23. For example, such aconfiguration may be possible in which the electrode body is providedwith a diameter increasing portion having almost the same outer diameteras the inner diameter of the tubular portion 13 and a diameter reducingportion whose outer diameter is smaller than the diameter increasingportion at locations different in the axial directions.

(4) The shapes of the spacer 27 and 29 are not limited to a square tubeand a cylindrical shape in the embodiments, and may have other shapes.For example, the shapes may be in a rectangular tube, an ellipticaltube, or an oblong tube. Moreover, the shapes are not limited to tubes.The shapes may be a shape having a filled inner space. In the case of ashape having a filled inner space, a member to be filled may be amartial the same as the materials of the spacer 27 and 29 or a differentmaterial. It is noted that a spacer including a space is preferablebecause the material of the spacer can be reduced.

(5) In the embodiment above, the negative plate 26 is disposed onthroughout the outer face of the electrode body 23. However, the presentinvention is not limited thereto. For example, such a configuration maybe possible in which the negative plate is disposed on a part of theouter face of the electrode body 23 and the negative plate of the outerface contacts the inner face 13A of the tubular portion 13.

Seventh Aspect

A battery 10 according to one embodiment in a seventh aspect of thepresent invention will be described with reference to FIGS. 46 to 50.The battery 10 is an alkaline secondary battery such as a nickel-metalhydride rechargeable cell. For example, the battery 10 is a low capacitytype such as an AA battery (“R6” in the IEC (InternationalElectrotechnical Commission), and “AA” in the United States) having acapacity of 1800 mAh or less, or an AAA battery (“R03” in the IEC, and“AAA” in the United States) having a capacity of 650 mAh or less. In thedescription below, the near side in FIG. 46 is the front side of thebattery 10, the right side is the right side of the battery 10, and theupper side is the upper side of the battery 10.

As shown in FIG. 46, the battery 10 is configured by a battery case 11and an electrode body 23. The battery case 11 is made of a metal and hasa shape elongated in one direction. The battery case 11 is an example ofthe case, and configured by a battery case main body 12 and a cover 15,and includes an accommodation space S in the inside. It is noted thatone direction is a vertical direction in FIG. 46, the longitudinaldirection of the battery case 11, and a direction opposite to the cover15 and a closing portion 14, described later.

The battery case main body 12 has a nickel-plated surface, and becomes anegative electrode terminal of the battery 10 by electrically connectinga negative plate 26, described later. The battery case main body 12 hasa shape in which one end is opened and the other end is closed in thevertical direction. More specifically, the battery case main body 12includes a tubular portion 13 and the closing portion 14.

The tubular portion 13 has a cylindrical shape elongated in the verticaldirection, and the shape of the inner circumferential face seen from thevertical direction is in a perfect circle in which an inner diameter Rpassing through a center axis W along the vertical direction isconstant. The inside of the tubular portion 13 is the accommodationspace S in which an electrode body 23, described later, can beaccommodated.

At one end of the tubular portion 13 in one direction, that is, at thetop end in FIG. 46, an opening 12A is formed to communicate with theinside of the tubular portion 13. The other end of the tubular portion13 in one direction, that is, at the top end in FIG. 46 is closed withthe closing portion 14. The closing portion 14 is a circular platemember, and integrally formed with the tubular portion 13.

The cover 15 is electrically connected to a positive plate 24, describedlater, through an elastic connecting terminal 21, and becomes a positiveelectrode terminal of the battery 10. The cover 15 includes a cover mainbody 16, an elastic body 18, and a terminal plate 19. The cover mainbody 16 is a circular flat plate, made of a conductive material such asa nickel-plated iron material, for example, and electrically connectedto the positive plate 24 through the connecting terminal 21. A throughhole 17 is formed in the center part of the cover main body 16.

The elastic body 18 is disposed on the top face of the cover main body16, that is, on the other side of the face opposite to the closingportion 14 in such a way that the elastic body 18 blocks the throughhole 17. The elastic body 18 is made of a material such as rubber, forexample, and elastically deformed by an external force. The terminalplate 19 is a conductive plate covering the elastic body 18.

More specifically, the terminal plate 19 is electrically connected tothe cover main body 16 in the state in which the terminal plate 19presses the elastic body 18 downward, that is, presses the elastic body18 against the cover main body 16. The terminal plate 19 is providedwith a discharge hole 20 to emit a gas in the battery case 11. Forexample, when the internal pressure of the battery case 11 is increasedand a pressure of a predetermined value or more is applied to theelastic body 18 through the through hole 17, the elastic body 18 iselastically deformed to communicate the inside of the battery case 11with the discharge hole 20, and a gas in the battery case 11 isdischarged to the outside of the battery 10 through the discharge hole20.

An elastically deformable insulator 22 is sandwiched between the opening12A of the battery case main body 12 and the cover 15 for sealing. Theinsulator 22 insulates the battery case main body 12 from the cover 15.

The electrode body 23 is accommodated in the accommodation space S inthe battery case 11. The electrode body 23 includes the positive plate24, the negative plate 26, and a separator 25 disposed between them andhaving an electrolyte, which are wound in a coiled shape as a windingaxis along the vertical direction is in the center. It is noted that thewinding axis may be matched with the center axis W or not. However, inthe following, for convenience of explanation, the winding axis ismatched with the center axis W.

The positive plate 24 (an example of one electrode plate) is formed of apositive metal plate 24A (an example of the substrate) coated with apositive active material 24B (an example of the active material). Thepositive metal plate 24A is made of nickel foam, for example. Thepositive active material 24B is a mixture of a positive nickel hydroxideactive material and a conductive cobalt compound. The positive plate 24is formed in which the positive active material 24B is coated in hollowspaces in the positive metal plate 24A.

It is noted that in the case where the battery 10 is a nickel-cadmiumrechargeable cell, the positive active material 24B is made of nickelhydroxide, for example, and in the case where the battery 10 is anickel-metal hydride rechargeable cell, the nickel hydroxide activematerial is nickel hydroxide added with calcium hydroxide, for example.

The negative plate 26 (one of the other electrode plate) includes thenegative metal plate 26A (an example of the substrate) coated with thenegative active material 26B (an example of an active material of theother polarity). The negative metal plate 26A is a flat, nickel-platedbored steel sheet, for example. The negative active material 26B ispowder such as cadmium powder and hydrogen storage alloy powder (anexample of an active material of one polarity), for example. Thenegative plate 26 is formed of the negative metal plate 26A coated withthe negative active material 26B.

It is noted that the negative active material 26B is a mixture ofcadmium oxide powder and metal cadmium powder, for example, in the caseof a nickel-cadmium rechargeable cell, whereas the negative activematerial is hydrogen storage alloy powder mainly of AB5 type (rareearth-Ni), AB3.0-3.8 type (rare earth-Mg—Ni), or AB2 type (Laves phase),for example, in the case of a nickel-metal hydride rechargeable cell.

Moreover, as shown in FIG. 48, in the electrode body 23, in a centerportion CT wound at a position close to a center axis W in thelongitudinal direction and the lateral direction, the length of theelectrode body 23 in the vertical direction is longer than a peripheralportion AR wound around the center portion CT. Either the positiveactive material 24B or the negative active material 26B is not coated onthe center portion CT.

On the other hand, the positive active material 24B or the negativeactive material 26B is coated on the peripheral portion AR. It is notedthat a region in which the negative active material 26B is coated isreferred to as a region TF. As described later in detail in FIG. 50, aregion TS in which the positive active material 24B is coated exists asopposite to the region TF.

It is noted that the inner diameter R of the tubular portion 13 issubstantially equal to an outer diameter L of the electrode body 23 (theouter diameter dimension of combining the center portion CT with theperipheral portion AR in the lateral direction in FIG. 47). Thus, theelectrode body 23 contacts an inner side face K (an example of an innerwall) of the tubular portion 13. The inner side face K of the tubularportion 13 is a face along the vertical direction in the inner face ofthe battery case 11. Moreover, in the electrode body 23, the lower partof the center portion CT in the vertical direction contacts the innerface of the closing portion 14 (an example of an inner wall).

FIG. 49 is a development view of the electrode body 23 unfolded. It isnoted that the vertical direction in FIG. 49 is the same as the verticaldirection in FIG. 48, and the lateral direction in FIG. 49 is the sameas the lateral direction in FIG. 48. In other words, FIG. 49 is a viewthat the electrode body 23 is unfolded and developed in the lateraldirection in FIG. 48. It is noted that in FIG. 49, the lateral directionof the electrode body 23, that is, the winding direction of theelectrode body 23 is an example of the longitudinal direction of theelectrode body 23. The vertical direction of the electrode body 23, thatis, the direction perpendicular to the winding direction of theelectrode body 23 is an example of the width.

As shown in FIG. 49, on the left side of the lateral direction of thepositive metal plate 24A, that is, on the left side of the windingdirection of the positive metal plate 24A, there is a region NS (anexample of a wide width portion) in which the width in the verticaldirection is wider than the width on the right side. The positive activematerial 24B is not coated on the region NS, and the region NS existsacross a length D1 in the lateral direction of the positive metal plate24A.

On the right side in the lateral direction of the positive metal plate24A, a region TS (an example of a narrow width portion) exists in whichthe width in the vertical direction is narrower than the width in theregion NS on the left side. In the region TS, the positive activematerial 24B is coated to form an active material layer, existing acrossa length D2 in the lateral direction of the positive metal plate 24A. Itis noted that the length D2 is longer than the length D1. Moreover, theregion TS is shorter by a length P1 from the top end of the positivemetal plate 24A in the vertical direction than in the region NS, and isshorter by a length P2 from the lower end of the positive metal plate24A in the vertical direction. The length P1 and the length P2 are thesame lengths.

As shown in FIG. 49, on the left side in the lateral direction of thenegative metal plate 26A, that is, on the left side in the windingdirection of the negative metal plate 26A, a region NF (an example of awide width portion) exists in which the width in the vertical directionis wider than the width on the right side. The negative active material26B is not coated on the region NF, and the region NF exists across alength F1 in the lateral direction of the negative metal plate 26A.

On the right side in the lateral direction of the negative metal plate26A, the region TF (an example of a narrow width portion) exists inwhich the width in the vertical direction is narrower than the width inthe region NF on the left side. In the region TF, the negative activematerial 26B is coated to form an active material layer, and the regionTF exists across a length F2 in the lateral direction of the negativemetal plate 26A. It is noted that the length F2 is longer than thelength F1. Moreover, the region TF is shorter by a length R1 from thetop end of the negative metal plate 26A in the vertical direction thanin the region NF, and shorter by a length R2 from the lower end of thenegative metal plate 26A in the vertical direction. The length R1 andthe length R2 are the same lengths.

As shown in FIG. 50, in the case where the electrode body 23 ismanufactured, the positive metal plate 24A and the negative metal plate26A are wound in such a way that the region TS in which the positiveactive material 24B is coated on the positive metal plate 24A isdisposed opposite to the region TF in which the negative active material26B is coated on the negative metal plate 26A. In other words, in thepositive metal plate 24A and the negative metal plate 26A, the length D1and the length F1 are equal, the length D2 and the length F2 are equal,the length P1 and the length R1 are equal, and the length P2 and thelength R2 are equal.

Since the region TS in which the positive active material 24B is coatedis disposed opposite to the region TF in which the negative activematerial 26B is coated, a current is produced across the region TS andthe region TF due to an electrochemical reaction.

Since the region NS in which the positive active material 24B is notcoated is the conductive positive metal plate 24A, the current producedin the region TS is passed through the positive metal plate 24A.Similarly, since the region NF in which the negative active material 26Bis not coated is the conductive negative metal plate 26A, the currentproduced in the region TF is passed through the negative metal plate26A.

Therefore, the amount of electrodes used can be suppressed as comparedwith a configuration in which the active material is coated throughoutthe metal plate.

The separator 25 is made of polyolefin nonwoven fabric, for example. Theseparator 25 is impregnated with an electrolyte containing primarilypotassium hydroxide or sodium hydrate. The separator 25 is not disposedon a face opposite to the inner side face K of the tubular portion 13 inthe electrode body 23, and the negative plate 26 is disposed on a faceopposite to the inner side face K of the tubular portion 13.

It is noted that as shown in FIG. 49, a region SH1 (an example of a widewidth portion) in which the width in the vertical direction is widerthan the width on the right side exists on the left side of theseparator 25 in the lateral direction. The region SH1 exists across alength E1 of the separator 25 in the lateral direction.

A region SH2 (an example of a narrow width portion) in which the widthin the vertical direction is narrower than the width in the region SH1on the left side exists on the right side of the separator 25 in thelateral direction. The region SH2 exists across a length E2 of theseparator 25 in the lateral direction. It is noted that the length E2 islonger than the length E1. Moreover, the region SH2 is shorter by alength Q1 from the top end of the separator 25 in the vertical directionthan in the region SH1, and shorter by a length Q2 from the lower end ofthe separator 25 in the vertical direction. The length Q1 and the lengthQ2 are the same lengths.

The separator 25 is wound together with the positive plate 24 and thenegative plate 26 in the state in which the region SH1 is opposite tothe region NS and the region NF. Furthermore, the separator 25 is woundtogether with the positive plate 24 and the negative plate 26 in thestate in which the region SH2 is opposite to the region TS and theregion TF. Therefore, in the positive metal plate 24A, the negativemetal plate 26A, and the separator 25, the length D1, the length F1, andthe length E1 are equal, the length D2, the length F2, and the length E2are equal, the length P1, the length R1, and the length Q1 are equal,and the length P2, the length R2, and the length Q2 are equal.

Effects of the Embodiment

According to this embodiment, the positive metal plate 24A includes theregion NS in which the positive active material 24B is not coated andthe region TS in which the positive active material 24B is coated andthe length in the vertical direction is shorter than the region NS. Theregion TS in which the positive active material 24B is coated on thepositive metal plate 24A is the positive plate 24.

Moreover, the negative metal plate 26A includes the region NF in whichthe negative active material 26B is not coated and the region TF inwhich the negative active material 26B is coated and the length in thevertical direction is shorter than the region NF. The region TF in whichthe negative active material 26B is coated on the negative metal plate26A is the negative plate 26.

In the electrode body 23, the positive metal plate 24A and the negativemetal plate 26A are wound in such a way that the region TS in which thepositive active material 24B is coated on the positive metal plate 24Ais disposed opposite to the region TF in which the negative activematerial 26B is coated on the negative metal plate 26A. Therefore, theamount of electrodes used can be suppressed, and the amounts ofmaterials to form the electrode body can be suppressed as compared witha configuration in which the region TS and the region TF are notprovided. The amounts of materials to form the electrode body can bedecreased, so that the weight of the battery can be reduced.

Furthermore, the positive metal plate 24A includes the region NS inwhich the length in the vertical direction is longer than in the regionTS, and the negative metal plate 26A includes the region NF in which thelength in the vertical direction is longer than in the region TF. Theconfiguration is made such that the region NS and the region NF arewound opposite to each other. Therefore, the unsteadiness of theelectrode body 23 in the battery case 11 can be suppressed as comparedwith a configuration in which the length in the vertical direction ismade shorter across the longitudinal direction and the lateral directionof the positive metal plate 24A and the negative metal plate 26A.

In addition, the positive metal plate 24A includes the region NS and theregion TS, and the negative metal plate 26A includes the region NF andthe region TF. In the electrode body 23, the region NS and the region NFare wound opposite to each other, and the region TS and the region TFare wound opposite to each other. In other words, the center portion CTand the peripheral portion AR are formed using the same single metalplate. Thus, it can be suppressed that the center portion CT and theperipheral portion AR are relatively unstable as compared with aconfiguration in which the center portion CT and the peripheral portionAR are separate products.

Other Embodiments

The techniques disclosed herein are not limited to the embodimentdescribed with reference to the drawings, and various forms below arealso included, for example.

In the embodiment above, an example is taken in which the electrode body23 has a cylindrical shape in which the positive plate 24, the negativeplate 26, and the separator 25 are wound counterclockwise as the centeraxis W is in the center. However, the embodiment is not limited thereto.Such a configuration may be possible in which the electrode body 23 isformed in a square shape in which a flat positive plate 24, a flatnegative plate 26, and a flat separator 25 are laid on each other toform a square shape as a whole, for example.

As shown in FIG. 51, the electrode body 23 may be configured such thatthe separator 25 does not include the region SH2. Moreover, such aconfiguration may be possible in which the region TF of the negativemetal plate 26A is wider than in the region TS of the positive metalplate 24A in the upper and lower parts in the vertical direction.Furthermore, such a configuration may be possible in which the region TSof the positive metal plate 24A is wider than in the region TF of thenegative metal plate 26A in the upper and lower parts in the verticaldirection.

In addition, as shown in FIG. 51, the electrode body 23 may beconfigured such that the positive active material 24B coated only on theregion TS of the positive metal plate 24A is also coated on the regionNS. More specifically, such a configuration may be possible in which thepositive active material 24B is not coated on the region of the lengthP1 from the top end of the region NS in the vertical direction and theregion of the length P2 from the lower end of the region NS in thevertical direction, and the positive active material 24B is coated onthe region NS by a length Z the same length as the region TS in thevertical direction of the region NS.

Moreover, the electrode body 23 may be configured such that the negativeactive material 26B coated only on the region TF of the negative metalplate 26A is also coated on the region NF. More specifically, such aconfiguration may be possible in which the negative active material 26Bis not coated on the region of the length P1 from the top end of theregion NF in the vertical direction and the region of the length P2 fromthe lower end of the region NF in the vertical direction, and thenegative active material 26B is coated on the region NF by the length Zthe same length as the region TF in the vertical direction of the regionNF.

In the embodiment above, an example is taken in which the tubularportion 13 has a cylindrical shape. However, the embodiment is notlimited thereto. The tubular portion 13 may have a square shape.

In the embodiment above, the configuration is taken as an example inwhich the length P1 from the top end of the positive metal plate 24A inthe vertical direction and the length P2 from the lower end of thepositive metal plate 24A in the vertical direction have the same lengthsin the vertical direction. However, the embodiment is not limitedthereto. The length P1 and the length P2 may be different in the lengthin the vertical direction. It is noted that the length Q1 from the topend of the separator 25 in the vertical direction, the length Q2 fromthe lower end of the separator 25 in the vertical direction, the lengthR1 from the top end of the negative metal plate 26A in the verticaldirection, and the length R2 from the lower end of the negative metalplate 26A in the vertical direction are also different in the verticaldirection.

In the embodiment above, the configuration is taken as an example inwhich the length D2 of the positive metal plate 24A in the lateraldirection where the region NS exists is longer than the length D1 of thepositive metal plate 24A in the lateral direction where the region TSexists. However, the embodiment is not limited thereto. The length D1and the length D2 may be the same in the lateral direction. It is notedthat the length E1 of the separator 25 in the lateral direction wherethe region SH1 exists, the length E2 of the separator 25 in the lateraldirection where the region SH2 exists, the length F1 of the negativemetal plate 26A in the lateral direction where the region NF exists, andthe length F2 of the negative metal plate 26A in the lateral directionwhere the region TS exists may also be the same in the lateraldirection.

In the embodiment above, an example is taken in which in the electrodebody 23, in the center portion CT wound at a position close to thecenter axis W in the longitudinal direction and the lateral direction,the length of the electrode body 23 in the vertical direction is longerthan the peripheral portion AR wound around the center portion CT.However, the embodiment is not limited thereto. The center portion CTmay be configured such that the length of the electrode body 23 in thevertical direction is shorter than the peripheral portion AR. However,since the peripheral portion AR has a longer diameter when the electrodebody 23 is wound, that is, the peripheral portion AR has a longer lengthfrom the center axis W of the electrode body 23 in the longitudinaldirection and the lateral direction than in the center portion CT, thelength in the circumferential direction is increased as the center axisW is in the center. Therefore, the used amounts of the positive metalplate 24A and the negative metal plate 26A are increased more than inthe configurations of the embodiment. Therefore, the configuration ofthe embodiment is more effective.

In the embodiment above, an example is taken in which the center portionCT is configured by the positive plate 24, the separator 25, thenegative plate 26. However, the embodiment is not limited thereto. Thecenter portion CT may be configured only by the separator 25. With thisconfiguration, the martial amounts of the metal plate and the activematerial are further decreased, so that the amount of electrodes usedcan be further decreased more than in the configuration of theembodiment. In this case, the separator 25 in the center portion CT isthermally welded to the separator 25 in the peripheral portion AR forforming an integral form.

In the embodiment above, the configuration is taken as an example inwhich the lengths of the region TS, the region TF, and the region SH2 inthe vertical direction are the same length Z across the lateraldirection. However, the embodiment is not limited thereto. Such aconfiguration may be possible in which the lengths of the region TS, theregion TF, and the region SH2 in the vertical direction are differentlengths across the lateral direction. Moreover, the lengths may bepartially the same lengths.

1-6. (canceled)
 7. A battery comprising: a case having an accommodationspace in the case; and an electrode body disposed in the accommodationspace in the case, and including positive and negative plates, each ofthe positive and negative plates having an active material layerincluding an active material and a substrate, and separator, whereineach of the positive and negative plates has an active material layerforming portion in which the active material layer is formed on thesubstrate and a non-active material layer forming portion in which theactive material layer is not formed, and the non-active material layerforming portions of the positive and negative plates directly andperpendicularly contact an inner wall of the case.
 8. The batteryaccording to claim 7, wherein the electrode body has a pair of thenon-active material layer forming portions on both ends of the electrodebody, and the active material layer forming portion is provided betweenthe pair of the non-active material layer forming portions.
 9. Thebattery according to claim 7, wherein the plurality of electrode platesis configured by a positive plate and a negative plate, the separator isdisposed between the positive plate and the negative plate, and both ofthe positive plate and the negative plate include the active materiallayer forming portion and the non-active material layer forming portion.10. The battery according to claim 7, wherein the substrate is a porousbody. 11-16. (canceled)
 17. The battery according to claim 7, whereinone electrode plate of the plurality of electrode plates has nickelhydroxide as the active material, and the other electrode plate of theplurality of electrode plates has a hydrogen storage alloy as the activematerial.
 18. (canceled)